MIPS: o32: Get rid of useless wrapper for llseek
Subsystems (2)
PATCH 2/2 MIPS: o32: Get rid of useless wrapper for llseek
arch/mips/kernel/linux32.c | 7 ------- arch/mips/kernel/scall64-o32.S | 2 +- 2 files changed, 1 insertions(+), 8 deletions(-)
arch/mips/kernel/linux32.c +0 -7
@@ -133,13 +133,6 @@ SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,return sys_ftruncate (fd,merge_64 (a2, a3)); } -SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high, - unsigned long, offset_low, loff_t __user *, result, - unsigned long, origin) -{ -return sys_llseek (fd, offset_high, offset_low, result, origin); -} -/* From the Single Unix Spec: pread & pwrite act like lseek to pos + op + lseek back to original location. They fail just like lseek does on non-seekable files. */
arch/mips/kernel/scall64-o32.S +1 -1
@@ -343,7 +343,7 @@ sys_call_table: PTR sys_ni_syscall /* for afs_syscall */ PTR sys_setfsuid PTR sys_setfsgid - PTR sys_32_llseek /* 4140 */ + PTR sys_llseek /* 4140 */ PTR compat_sys_getdents PTR compat_sys_select PTR sys_flock
Quoted 11 lines · On Wed, 25 Mar 2009 01:15:55 +0100 Ralf Baechle <[email protected]> wrote:
Signed-off-by Ralf Baechle <[email protected]>arch/mips/kernel/linux32.c | 7 ------- arch/mips/kernel/scall64-o32.S | 2 +- 2 files changed, 1 insertions(+), 8 deletions(-)arch/mips/kernel/linux32.c +0
-0
arch/mips/kernel/linux32.c SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy, · line 142
Quoted 10 lines
arch/mips/kernel/linux32.c +0
-7@@ -133,13 +133,6 @@ SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,return sys_ftruncate (fd,merge_64 (a2, a3)); } -SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high, - unsigned long, offset_low, loff_t __user *, result, - unsigned long, origin) -{ -return sys_llseek (fd, offset_high, offset_low, result, origin); -} -
Ah.. this hunk seems to be the origin of the bug. git commit dbda6ac0897603f6c6dfadbbc37f9882177ec7ac "MIPS: CVE-2009-0029: Enable syscall wrappers." contains this:
-asmlinkage int sys32_llseek(unsigned int fd, unsigned int offset_high,
- unsigned int offset_low, loff_t __user * result,
- unsigned int origin)
+SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high,
+ unsigned long, offset_low, loff_t __user *, result,
+ unsigned long, origin)
Here you converted offset_low from unsigned int to unsigned long. Hence you lost the clearing of the upper 32 bits. That would explain the bug. Any chance the process where the bug was seen was a compat process?
Patch below would probably fix it.
Btw. there are a lot of int->long conversions in the git commit mentioned above. AFAICS all(?) of the conversions are wrong.
arch/mips/kernel/linux32.c +3 -3
@@ -134,9 +134,9 @@ SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,return sys_ftruncate (fd,merge_64 (a2, a3)); } -SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high, - unsigned long, offset_low, loff_t __user *, result, - unsigned long, origin) +SYSCALL_DEFINE5(32_llseek, unsigned int, fd, unsigned int, offset_high, + unsigned int, offset_low, loff_t __user *, result, + unsigned int, origin) {return sys_llseek (fd, offset_high, offset_low, result, origin); }
Quoted 36 lines · Heiko Carstens
Quoted 11 lines · On Wed, 25 Mar 2009 01:15:55 +0100 Ralf Baechle <[email protected]> wrote:
Signed-off-by Ralf Baechle <[email protected]>arch/mips/kernel/linux32.c | 7 ------- arch/mips/kernel/scall64-o32.S | 2 +- 2 files changed, 1 insertions(+), 8 deletions(-)arch/mips/kernel/linux32.c +0
-0arch/mips/kernel/linux32.c SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy, · line 142
Quoted 10 lines
arch/mips/kernel/linux32.c +0
-7@@ -133,13 +133,6 @@ SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,return sys_ftruncate (fd,merge_64 (a2, a3)); } -SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high, - unsigned long, offset_low, loff_t __user *, result, - unsigned long, origin) -{ -return sys_llseek (fd, offset_high, offset_low, result, origin); -} -Ah.. this hunk seems to be the origin of the bug. git commit
dbda6ac0897603f6c6dfadbbc37f9882177ec7ac"MIPS: CVE-2009-0029: Enable syscall wrappers." contains this:(quoted diff) +3
-3-asmlinkage int sys32_llseek(unsigned int fd, unsigned int offset_high, - unsigned int offset_low, loff_t __user * result, - unsigned int origin) +SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high, + unsigned long, offset_low, loff_t __user *, result, + unsigned long, origin)
Quoted 3 lines
Here you converted
offset_lowfrom unsigned int to unsigned long. Hence you lost the clearing of the upper 32 bits. That would explain the bug. Any chance the process where the bug was seen was a compat process?
$ file /sbin/e2fsck /sbin/e2fsck: ELF 32-bit MSB executable, MIPS, MIPS-I version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.8, with unknown capability 0x41000000 = 0xf676e75, stripped
Quoted 1 line
Patch below would probably fix it.
This patch works for me on the aforementioned Debian system.
Quoted 21 lines
Btw. there are a lot of
int->longconversions in the git commit mentioned above. AFAICS all(?) of the conversions are wrong.arch/mips/kernel/linux32.c +3
-3@@ -134,9 +134,9 @@ SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,return sys_ftruncate (fd,merge_64 (a2, a3)); } -SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high, - unsigned long, offset_low, loff_t __user *, result, - unsigned long, origin) +SYSCALL_DEFINE5(32_llseek, unsigned int, fd, unsigned int, offset_high, + unsigned int, offset_low, loff_t __user *, result, + unsigned int, origin) {return sys_llseek (fd, offset_high, offset_low, result, origin); }
Signature · 1 line
dann frazier
Quoted 1 line · Ralf Baechle
Signed-off-by Ralf Baechle <[email protected]>
Quoted 36 lines
arch/mips/kernel/linux32.c | 7 ------- arch/mips/kernel/scall64-o32.S | 2 +- 2 files changed, 1 insertions(+), 8 deletions(-)arch/mips/kernel/linux32.c +0
-7@@ -133,13 +133,6 @@ SYSCALL_DEFINE4(32_ftruncate64, unsigned long, fd, unsigned long, __dummy,return sys_ftruncate (fd,merge_64 (a2, a3)); } -SYSCALL_DEFINE5(32_llseek, unsigned long, fd, unsigned long, offset_high, - unsigned long, offset_low, loff_t __user *, result, - unsigned long, origin) -{ -return sys_llseek (fd, offset_high, offset_low, result, origin); -} -/* From the Single Unix Spec: pread & pwrite act like lseek to pos + op + lseek back to original location. They fail just like lseek does on non-seekable files. */ arch/mips/kernel/scall64-o32.S +1
-1@@ -343,7 +343,7 @@ sys_call_table: PTR sys_ni_syscall /* for afs_syscall */ PTR sys_setfsuid PTR sys_setfsgid - PTR sys_32_llseek /* 4140 */ + PTR sys_llseek /* 4140 */ PTR compat_sys_getdents PTR compat_sys_select PTR sys_flock
Signature · 1 line
dann frazier