BPF/random32 updates
Subsystems (7)
Daniel Borkmann
maintainerv2 cover BPF/random32 updates
BPF update to split the prandom state apart, and to move the *once helpers to the core. For details, please see individual patches. Given the changes and since it's in the tree for quite some time, net-next is a better choice in our opinion.
v1 -> v2:
- Make DO_ONCE() type-safe, remove the kvec helper. Credits go to Alexei Starovoitov for the __VA_ARGS__ hint, thanks!
- Add a comment to the DO_ONCE() helper as suggested by Alexei.
- Rework prandom_init_once() helper to the new API.
- Keep Alexei's Acked-by on the last patch.
Thanks!
Daniel Borkmann (3):
random32: add prandom_seed_full_state helper
random32: add prandom_init_once helper for own rngs
bpf: split state from prandom_u32() and consolidate {c,e}BPF prngs
Hannes Frederic Sowa (2):
net: move net_get_random_once to lib
once: make helper generic for calling function once
include/linux/bpf.h | 4 ++++ include/linux/net.h | 21 ++++------------- include/linux/once.h | 57 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/random.h | 6 +++++ kernel/bpf/core.c | 26 +++++++++++++++++++++ kernel/bpf/helpers.c | 7 +----- kernel/bpf/syscall.c | 2 ++ lib/Makefile | 3 ++- lib/once.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++ lib/random32.c | 37 +++++++++++++++++------------- net/core/filter.c | 9 ++------ net/core/utils.c | 49 --------------------------------------- 12 files changed, 187 insertions(+), 96 deletions(-) create mode 100644 include/linux/once.h create mode 100644 lib/once.c
Signature · 1 line
1.9.3
Daniel Borkmann
maintainerPATCH v2 1/5 net: move net_get_random_once to lib
From: Hannes Frederic Sowa <[email protected]>
There's no good reason why users outside of networking should not be using this facility, f.e. for initializing their seeds.
Therefore, make it accessible from there as get_random_once().
--- include/linux/net.h | 21 ++++---------------- include/linux/once.h | 24 +++++++++++++++++++++++ lib/Makefile | 3 ++- lib/once.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++ net/core/utils.c | 49 ----------------------------------------------- 5 files changed, 84 insertions(+), 67 deletions(-) create mode 100644 include/linux/once.h create mode 100644 lib/once.c
include/linux/net.h +4 -17
@@ -24,7 +24,8 @@#include <linux/fcntl.h> /* For O_CLOEXEC and O_NONBLOCK */ #include <linux/kmemcheck.h> #include <linux/rcupdate.h> -#include <linux/jump_label.h> +#include <linux/once.h> +#include <uapi/linux/net.h> struct poll_table_struct ;
@@ -250,22 +251,8 @@ do { \ } while (0)#endif -bool __net_get_random_once (void *buf,int nbytes,bool *done, -struct static_key *done_key); - -#define net_get_random_once (buf, nbytes) \ - ({ \ - bool ___ret = false; \ - static bool ___done = false; \ - static struct static_key ___once_key = \ - STATIC_KEY_INIT_TRUE; \ - if (static_key_true(&___once_key)) \ - ___ret = __net_get_random_once(buf, \ - nbytes, \ - &___done, \ - &___once_key); \ - ___ret; \ - }) +#define net_get_random_once (buf, nbytes) \ + get_random_once((buf), (nbytes))int kernel_sendmsg (struct socket *sock,struct msghdr *msg,struct kvec *vec,size_t num,size_t len);
include/linux/once.h new file +24 -0
@@ -0,0 +1,24 @@ +#ifndef _LINUX_ONCE_H +#define _LINUX_ONCE_H + +#include <linux/types.h> +#include <linux/jump_label.h> + +bool __get_random_once (void *buf,int nbytes,bool *done, +struct static_key *once_key); + +#define get_random_once (buf, nbytes) \ + ({ \ + bool ___ret = false; \ + static bool ___done = false; \ + static struct static_key ___once_key = \ + STATIC_KEY_INIT_TRUE; \ + if (static_key_true(&___once_key)) \ + ___ret = __get_random_once((buf), \ + (nbytes), \ + &___done, \ + &___once_key); \ + ___ret; \ + }) + +#endif /* _LINUX_ONCE_H */
lib/Makefile +2 -1
@@ -26,7 +26,8 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \ gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \ bsearch.o find_bit.o llist.o memweight.o kfifo.o \ - percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o + percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o \ + once.o obj-y += string_helpers.o obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o obj-y += hexdump.o
lib/once.c new file +54 -0
54 lines not on this page · raw message
net/core/utils.c +0 -49
52 lines not on this page · raw message
Signature · 1 line
1.9.3
Re: [PATCH net-next v2 1/5] net: move net_get_random_once to lib
Quoted 9 lines · Daniel Borkmann
From: Hannes Frederic Sowa<[email protected]>
There's no good reason why users outside of networking should not be using this facility, f.e. for initializing their seeds.
Therefore, make it accessible from there as
get_random_once().Signed-off-by Hannes Frederic Sowa<[email protected]>Signed-off-by Daniel Borkmann<[email protected]>
kbuild test robot
build botRe: [PATCH net-next v2 1/5] net: move net_get_random_once to lib
In reply to Daniel Borkmannconfig: mips-ip27_defconfig (attached as .config) reproduce: wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross #…
Hi Hannes,
[auto build test WARNING on net-next/master -- if it's inappropriate base, please ignore]
config: mips-ip27_defconfig (attached as .config)
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=mips
All warnings (new ones prefixed by >>):
mips-linux-gnu-ld: lib/lockref.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/lockref.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bcd.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bcd.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/div64.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/div64.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/sort.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/sort.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/parser.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/parser.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/halfmd4.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/halfmd4.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/debug_locks.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/debug_locks.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/random32.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/random32.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bust_spinlocks.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bust_spinlocks.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/kasprintf.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/kasprintf.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bitmap.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bitmap.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/scatterlist.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/scatterlist.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/gcd.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/gcd.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/lcm.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/lcm.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/list_sort.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/list_sort.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/uuid.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/uuid.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/flex_array.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/flex_array.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/iov_iter.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/iov_iter.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/clz_ctz.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/clz_ctz.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bsearch.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bsearch.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/find_bit.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/find_bit.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/llist.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/llist.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/memweight.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/memweight.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/kfifo.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/kfifo.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/percpu-refcount.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/percpu-refcount.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/percpu_ida.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/percpu_ida.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/rhashtable.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/rhashtable.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/reciprocal_div.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/reciprocal_div.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
>> mips-linux-gnu-ld: lib/once.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags >> mips-linux-gnu-ld: lib/once.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/string_helpers.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/string_helpers.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/hexdump.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/hexdump.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/kstrtox.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/kstrtox.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/pci_iomap.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/pci_iomap.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/iomap_copy.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/iomap_copy.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/devres.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/devres.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/check_signature.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/check_signature.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/hweight.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/hweight.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/assoc_array.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/assoc_array.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bitrev.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/bitrev.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/rational.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/rational.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/crc16.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/crc16.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/crc32.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/crc32.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/percpu_counter.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/percpu_counter.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/syscall.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/syscall.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/nlattr.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/nlattr.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/cpu_rmap.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/cpu_rmap.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/dynamic_queue_limits.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/dynamic_queue_limits.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/net_utils.o: warning: Inconsistent ISA between e_flags and .MIPS.abiflags
mips-linux-gnu-ld: lib/net_utils.o: warning: Inconsistent ISA extensions between e_flags and .MIPS.abiflags
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Daniel Borkmann
maintainerRe: [PATCH net-next v2 1/5] net: move net_get_random_once to lib
Quoted 15 lines · kbuild test robot
Hi Hannes,
[auto build test WARNING on net-next/master -- if it's inappropriate base, please ignore]
config: mips-ip27_defconfig (attached as .config)
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=mipsAll warnings (new ones prefixed by >>):
mips-linux-gnu-ld:
lib/lockref.o: warning: Inconsistent ISA betweene_flagsand .MIPS.abiflags
mips-linux-gnu-ld:lib/lockref.o: warning: Inconsistent ISA extensions betweene_flagsand .MIPS.abiflags
[...]
Quoted 4 lines
mips-linux-gnu-ld:
lib/reciprocal_div.o: warning: Inconsistent ISA betweene_flagsand .MIPS.abiflags
mips-linux-gnu-ld:lib/reciprocal_div.o: warning: Inconsistent ISA extensions betweene_flagsand .MIPS.abiflagsQuoted 2 lines
Quoted 2 lines
mips-linux-gnu-ld:
lib/once.o: warning: Inconsistent ISA betweene_flagsand .MIPS.abiflags
mips-linux-gnu-ld:lib/once.o: warning: Inconsistent ISA extensions betweene_flagsand .MIPS.abiflags
Looks like a known issue on MIPS given the warning is not new also on other object files. Here was what was discussed recently on this subject on a refactoring patch from David Ahern:
https://patchwork.ozlabs.org/patch/525102/
Thanks!
Quoted 2 lines
mips-linux-gnu-ld:
lib/string_helpers.o: warning: Inconsistent ISA betweene_flagsand .MIPS.abiflags
mips-linux-gnu-ld:lib/string_helpers.o: warning: Inconsistent ISA extensions betweene_flagsand .MIPS.abiflags
[...]
Daniel Borkmann
maintainerPATCH v2 2/5 once: make helper generic for calling functions once
In reply to Daniel BorkmannFrom: Hannes Frederic Sowa <[email protected]>
Make the get_random_once() helper generic enough, so that functions in general would only be called once, where one user of this is then net_get_random_once().
The only implementation specific call is to get_random_bytes(), all the rest of this *_once() facility would be duplicated among different subsystems otherwise. The new DO_ONCE() helper will be used by prandom() later on, but might also be useful for other scenarios/subsystems as well where a one-time initialization in often-called, possibly fast path code could occur.
--- include/linux/once.h | 61 ++++++++++++++++++++++++++++++++++++++++------------ lib/once.c | 50 ++++++++++++++++++++++++------------------ 2 files changed, 76 insertions(+), 35 deletions(-)
include/linux/once.h +47 -14
@@ -4,21 +4,54 @@#include <linux/types.h> #include <linux/jump_label.h> -bool __get_random_once (void *buf,int nbytes,bool *done, -struct static_key *once_key); +bool __do_once_start (bool *done,unsigned long *flags); +void __do_once_done (bool *done,struct static_key *once_key, +unsigned long *flags); -#define get_random_once (buf, nbytes) \ - ({ \ - bool ___ret = false; \ - static bool ___done = false; \ - static struct static_key ___once_key = \ - STATIC_KEY_INIT_TRUE; \ - if (static_key_true(&___once_key)) \ - ___ret = __get_random_once((buf), \ - (nbytes), \ - &___done, \ - &___once_key); \ - ___ret; \ +/* Call a function exactly once. The idea of DO_ONCE() is to perform +* a function call such as initialization of random seeds, etc, only +* once, where DO_ONCE() can live in the fast-path. After @func has +* been called with the passed arguments, the static key will patch +* out the condition into a nop. DO_ONCE() guarantees type safety of +* arguments! +* +* Not that the following is not equivalent ... +* +* DO_ONCE(func, arg); +* DO_ONCE(func, arg); +* +* ... to this version: +* +* void foo(void) +* { +* DO_ONCE(func, arg); +* } +* +* foo(); +* foo(); +* +* In case the one-time invocation could be triggered from multiple +* places, then a common helper function must be defined, so that only +* a single static key will be placed there! +*/ +#define DO_ONCE (func, ...) \ + ({ \ + bool ___ret = false; \ + static bool ___done = false; \ + static struct static_key ___once_key = STATIC_KEY_INIT_TRUE; \ + if (static_key_true(&___once_key)) { \ + unsigned long ___flags; \ + ___ret = __do_once_start(&___done, &___flags); \ + if (unlikely(___ret)) { \ + func(__VA_ARGS__); \ + __do_once_done(&___done, &___once_key, \ + &___flags); \ + } \ + } \ + ___ret; \ }) +#define get_random_once (buf, nbytes) \ + DO_ONCE(get_random_bytes, (buf), (nbytes)) +#endif /* _LINUX_ONCE_H */
lib/once.c +29 -21
81 lines not on this page · raw message
Signature · 1 line
1.9.3
Re: [PATCH net-next v2 2/5] once: make helper generic for calling functions once
Quoted 13 lines · Daniel Borkmann
From: Hannes Frederic Sowa<[email protected]>
Make the
get_random_once()helper generic enough, so that functions in general would only be called once, where one user of this is thennet_get_random_once().The only implementation specific call is to
get_random_bytes(), all the rest of this*_once()facility would be duplicated among different subsystems otherwise. The newDO_ONCE()helper will be used byprandom()later on, but might also be useful for other scenarios/subsystems as well where a one-time initialization in often-called, possibly fast path code could occur.
Quoted 2 lines
Signed-off-by Hannes Frederic Sowa<[email protected]>Signed-off-by Daniel Borkmann<[email protected]>
nice! you even added sparse tags.
Daniel Borkmann
maintainerPATCH v2 3/5 random32: add prandom_seed_full_state helper
In reply to Daniel BorkmannFactor out the full reseed handling code that populates the state through get_random_bytes() and runs prandom_warmup(). The resulting prandom_seed_full_state() will be used later on in more than the current __prandom_reseed() user. Fix also two minor whitespace issues along the way.
--- lib/random32.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-)
lib/random32.c +21 -16
@@ -181,7 +181,7 @@ void prandom_seed(u32 entropy)* No locking on the CPUs, but then somewhat random results are, well, * expected. */ -for_each_possible_cpu (i) { +for_each_possible_cpu (i) {struct rnd_state *state = &per_cpu (net_rand_state, i); state->s1 =__seed (state->s1 ^ entropy,2U );
@@ -201,7 +201,7 @@ static int __init prandom_init(void)prandom_state_selftest ();for_each_possible_cpu (i) { -struct rnd_state *state = &per_cpu (net_rand_state,i); +struct rnd_state *state = &per_cpu (net_rand_state, i);u32 weak_seed = (i + jiffies) ^random_get_entropy ();prandom_seed_early (state, weak_seed, true);
@@ -238,13 +238,30 @@ static void __init __prandom_start_seed_timer(void)add_timer (&seed_timer); } +static void prandom_seed_full_state (struct rnd_state __percpu *pcpu_state) +{ +int i; + +for_each_possible_cpu (i) { +struct rnd_state *state =per_cpu_ptr (pcpu_state, i); +u32 seeds[4 ]; + +get_random_bytes (&seeds,sizeof (seeds)); + state->s1 =__seed (seeds[0 ],2U ); + state->s2 =__seed (seeds[1 ],8U ); + state->s3 =__seed (seeds[2 ],16U ); + state->s4 =__seed (seeds[3 ],128U ); + +prandom_warmup (state); + } +} +/* * Generate better values after random number generator * is fully initialized. */ static void __prandom_reseed (bool late) { -int i;unsigned long flags;static bool latch = false;static DEFINE_SPINLOCK (lock);
@@ -266,19 +283,7 @@ static void __prandom_reseed(bool late) goto out; latch = true; - -for_each_possible_cpu (i) { -struct rnd_state *state = &per_cpu (net_rand_state,i); -u32 seeds[4 ]; - -get_random_bytes (&seeds,sizeof (seeds)); - state->s1 =__seed (seeds[0 ],2U ); - state->s2 =__seed (seeds[1 ],8U ); - state->s3 =__seed (seeds[2 ],16U ); - state->s4 =__seed (seeds[3 ],128U ); - -prandom_warmup (state); - } +prandom_seed_full_state (&net_rand_state); out:spin_unlock_irqrestore (&lock, flags); }
Signature · 1 line
1.9.3
Re: [PATCH net-next v2 3/5] random32: add prandom_seed_full_state helper
Quoted 8 lines · Daniel Borkmann
Factor out the full reseed handling code that populates the state through
get_random_bytes()and runsprandom_warmup(). The resultingprandom_seed_full_state()will be used later on in more than the current__prandom_reseed()user. Fix also two minor whitespace issues along the way.Signed-off-by Daniel Borkmann<[email protected]>
Daniel Borkmann
maintainerPATCH v2 4/5 random32: add prandom_init_once helper for own rngs
In reply to Daniel BorkmannAdd a prandom_init_once() facility that works on the rnd_state, so that users that are keeping their own state independent from prandom_u32() can initialize their taus113 per cpu states.
The motivation here is similar to net_get_random_once(): initialize the state as late as possible in the hope that enough entropy has been collected for the seeding. prandom_init_once() makes use of the recently introduced prandom_seed_full_state() helper and is generic enough so that it could also be used on fast-paths due to the DO_ONCE().
--- include/linux/random.h | 6 ++++++ lib/random32.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-)
include/linux/random.h +6 -0
@@ -7,6 +7,8 @@#define _LINUX_RANDOM_H#include <linux/list.h> +#include <linux/once.h> +#include <uapi/linux/random.h> struct random_ready_callback {
@@ -45,6 +47,10 @@ struct rnd_state {u32 prandom_u32_state (struct rnd_state *state);void prandom_bytes_state (struct rnd_state *state,void *buf,size_t nbytes); +void prandom_seed_full_state (struct rnd_state __percpu *pcpu_state); + +#define prandom_init_once (pcpu_state) \ + DO_ONCE(prandom_seed_full_state, (pcpu_state))/** * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
lib/random32.c +1 -1
@@ -238,7 +238,7 @@ static void __init __prandom_start_seed_timer(void)add_timer (&seed_timer); } -static void prandom_seed_full_state (struct rnd_state __percpu *pcpu_state) +void prandom_seed_full_state (struct rnd_state __percpu *pcpu_state) {int i;
Signature · 1 line
1.9.3
Re: [PATCH net-next v2 4/5] random32: add prandom_init_once helper for own rngs
Quoted 4 lines · Daniel Borkmann
Add a
prandom_init_once()facility that works on thernd_state, so that users that are keeping their own state independent fromprandom_u32()can initialize their taus113 per cpu states.
Quoted 8 lines
The motivation here is similar to
net_get_random_once(): initialize the state as late as possible in the hope that enough entropy has been collected for the seeding.prandom_init_once()makes use of the recently introducedprandom_seed_full_state()helper and is generic enough so that it could also be used on fast-paths due to theDO_ONCE().Signed-off-by Daniel Borkmann<[email protected]>
Daniel Borkmann
maintainerPATCH v2 5/5 bpf: split state from prandom_u32() and consolidate {c,e}BPF prngs
In reply to Daniel BorkmannWhile recently arguing on a seccomp discussion that raw prandom_u32() access shouldn't be exposed to unpriviledged user space, I forgot the fact that SKF_AD_RANDOM extension actually already does it for some time in cBPF via commit 4cd3675ebf74 ("filter: added BPF random opcode").
Since prandom_u32() is being used in a lot of critical networking code, lets be more conservative and split their states. Furthermore, consolidate eBPF and cBPF prandom handlers to use the new internal PRNG. For eBPF, bpf_get_prandom_u32() was only accessible for priviledged users, but should that change one day, we also don't want to leak raw sequences through things like eBPF maps.
One thought was also to have own per bpf_prog states, but due to ABI reasons this is not easily possible, i.e. the program code currently cannot access bpf_prog itself, and copying the rnd_state to/from the stack scratch space whenever a program uses the prng seems not really worth the trouble and seems too hacky. If needed, taus113 could in such cases be implemented within eBPF using a map entry to keep the state space, or get_random_bytes() could become a second helper in cases where performance would not be critical.
Both sides can trigger a one-time late init via prandom_init_once() on the shared state. Performance-wise, there should even be a tiny gain as bpf_user_rnd_u32() saves one function call. The PRNG needs to live inside the BPF core since kernels could have a NET-less config as well.
--- include/linux/bpf.h | 4 ++++ kernel/bpf/core.c | 26 ++++++++++++++++++++++++++ kernel/bpf/helpers.c | 7 +------ kernel/bpf/syscall.c | 2 ++ net/core/filter.c | 9 ++------- 5 files changed, 35 insertions(+), 13 deletions(-)
include/linux/bpf.h +4 -0
@@ -200,4 +200,8 @@ extern const struct bpf_func_proto bpf_get_current_comm_proto;extern const struct bpf_func_proto bpf_skb_vlan_push_proto;extern const struct bpf_func_proto bpf_skb_vlan_pop_proto; +/* Shared helpers among cBPF and eBPF. */ +void bpf_user_rnd_init_once (void ); +u64 bpf_user_rnd_u32 (u64 r1,u64 r2,u64 r3,u64 r4,u64 r5); +#endif /* _LINUX_BPF_H */
kernel/bpf/core.c +26 -0
@@ -731,6 +731,32 @@ void bpf_prog_free(struct bpf_prog *fp) }EXPORT_SYMBOL_GPL (bpf_prog_free); +/* RNG for unpriviledged user space with separated state from prandom_u32(). */ +static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); + +void bpf_user_rnd_init_once (void ) +{ +prandom_init_once (&bpf_user_rnd_state); +} + +u64 bpf_user_rnd_u32 (u64 r1,u64 r2,u64 r3,u64 r4,u64 r5) +{ +/* Should someone ever have the rather unwise idea to use some +* of the registers passed into this function, then note that +* this function is called from native eBPF and classic-to-eBPF +* transformations. Register assignments from both sides are +* different, f.e. classic always sets fn(ctx, A, X) here. +*/ +struct rnd_state *state; +u32 res; + + state = &get_cpu_var (bpf_user_rnd_state); + res =prandom_u32_state (state); +put_cpu_var (state); + +return res; +} +/* Weak definitions of helper functions in case we don't have bpf syscall. */ const struct bpf_func_proto bpf_map_lookup_elem_proto__weak ;const struct bpf_func_proto bpf_map_update_elem_proto__weak ;
kernel/bpf/helpers.c +1 -6
@@ -93,13 +93,8 @@ const struct bpf_func_proto bpf_map_delete_elem_proto = { .arg2_type = ARG_PTR_TO_MAP_KEY, }; -static u64 bpf_get_prandom_u32 (u64 r1,u64 r2,u64 r3,u64 r4,u64 r5) -{ -return prandom_u32 (); -} -const struct bpf_func_proto bpf_get_prandom_u32_proto = { - .func = bpf_get_prandom_u32, + .func = bpf_user_rnd_u32, .gpl_only = false, .ret_type =RET_INTEGER , };
kernel/bpf/syscall.c +2 -0
@@ -404,6 +404,8 @@ static void fixup_bpf_calls(struct bpf_prog *prog)if (insn->imm == BPF_FUNC_get_route_realm) prog->dst_needed =1 ; +if (insn->imm == BPF_FUNC_get_prandom_u32) +bpf_user_rnd_init_once ();if (insn->imm == BPF_FUNC_tail_call) {/* mark bpf_tail_call as different opcode * to avoid conditional branch in
net/core/filter.c +2 -7
@@ -149,12 +149,6 @@ static u64 __get_raw_cpu_id(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)return raw_smp_processor_id (); } -/* note that this only generates 32-bit random numbers */ -static u64 __get_random_u32 (u64 ctx,u64 a,u64 x,u64 r4,u64 r5) -{ -return prandom_u32 (); -} -static u32 convert_skb_access (int skb_field,int dst_reg,int src_reg,struct bpf_insn *insn_buf) {
@@ -313,7 +307,8 @@ static bool convert_bpf_extensions(struct sock_filter *fp, *insn =BPF_EMIT_CALL (__get_raw_cpu_id);break ;case SKF_AD_OFF +SKF_AD_RANDOM : - *insn =BPF_EMIT_CALL (__get_random_u32); + *insn =BPF_EMIT_CALL (bpf_user_rnd_u32); +bpf_user_rnd_init_once ();break ; }break ;
Signature · 1 line
1.9.3
David Miller
maintainerFrom: Daniel Borkmann <[email protected]>
Date: Thu, 8 Oct 2015 01:20:34 +0200
Quoted 11 lines
BPF update to split the prandom state apart, and to move the *once helpers to the core. For details, please see individual patches. Given the changes and since it's in the tree for quite some time, net-next is a better choice in our opinion.
v1 -> v2:
- MakeDO_ONCE()type-safe, remove the kvec helper. Credits go to Alexei Starovoitov for the__VA_ARGS__hint, thanks!
- Add a comment to theDO_ONCE()helper as suggested by Alexei.
- Reworkprandom_init_once()helper to the new API.
- Keep Alexei's Acked-by on the last patch.
Series applied, thanks everyone.