KASAN: slab-out-of-bounds Read in dns_resolver_preparse
Subsystems (4)
syzbot
syzbotHello,
syzbot found the following issue on:
HEAD commit: 48e8992e33ab Add linux-next specific files for 20231213 git tree: linux-next console+strace: https://syzkaller.appspot.com/x/log.txt?x=155c1ac1e80000 kernel config: https://syzkaller.appspot.com/x/.config?x=978b8aaa2e92a8f dashboard link: https://syzkaller.appspot.com/bug?extid=94bbb75204a05da3d89f compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e0a966e80000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1555a15ce80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/ade5327f8151/disk-48e8992e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/16bff810e759/vmlinux-48e8992e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/14c4448589de/bzImage-48e8992e.xz
The issue was bisected to:
commit b946001d3bb1202e90093cf5e72dbcb20e2689a0
Author: David Howells <[email protected]> Date: Sat Dec 9 00:41:55 2023 +0000
keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=10c349c1e80000 final oops: https://syzkaller.appspot.com/x/report.txt?x=12c349c1e80000 console output: https://syzkaller.appspot.com/x/log.txt?x=14c349c1e80000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
==================================================================
BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127 Read of size 1 at addr ffff888028894084 by task syz-executor265/5069 CPU: 0 PID: 5069 Comm: syz-executor265 Not tainted 6.7.0-rc5-next-20231213-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127 __key_create_or_update+0x453/0xdf0 security/keys/key.c:842 key_create_or_update+0x42/0x50 security/keys/key.c:1007 __do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x62/0x6a RIP: 0033:0x7fd37f34f2e9 Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff2f4f3198 EFLAGS: 00000246 ORIG_RAX: 00000000000000f8 RAX: ffffffffffffffda RBX: 00007fff2f4f3368 RCX: 00007fd37f34f2e9 RDX: 0000000020000080 RSI: 0000000000000000 RDI: 00000000200003c0 RBP: 00007fd37f3c2610 R08: 0000000002853c32 R09: 00007fff2f4f3368 R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000001 R13: 00007fff2f4f3358 R14: 0000000000000001 R15: 0000000000000001 </TASK> Allocated by task 5069: kasan_save_stack+0x33/0x50 mm/kasan/common.c:47 kasan_set_track+0x24/0x30 mm/kasan/common.c:61 ____kasan_kmalloc mm/kasan/common.c:375 [inline] __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slub.c:3985 [inline] __kmalloc_node+0x226/0x480 mm/slub.c:3992 kmalloc_node include/linux/slab.h:610 [inline] kvmalloc_node+0x99/0x1a0 mm/util.c:617 kvmalloc include/linux/slab.h:728 [inline] __do_sys_add_key+0x1f8/0x450 security/keys/keyctl.c:116 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x62/0x6a The buggy address belongs to the object at ffff888028894080 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of
allocated 4-byte region [ffff888028894080, ffff888028894084)
The buggy address belongs to the physical page:
page:ffffea0000a22500 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28894
anon flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888013041280 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080800080 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 1, tgid 1 (swapper/0), ts 27978623390, free_ts 27978121808
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1540
prep_new_page mm/page_alloc.c:1547 [inline]
get_page_from_freelist+0xa19/0x3740 mm/page_alloc.c:3355
__alloc_pages+0x22e/0x2410 mm/page_alloc.c:4611
alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133
alloc_slab_page mm/slub.c:2191 [inline]
allocate_slab mm/slub.c:2358 [inline]
new_slab+0x283/0x3c0 mm/slub.c:2411
___slab_alloc+0x4ab/0x1990 mm/slub.c:3544
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3629
__slab_alloc_node mm/slub.c:3682 [inline]
slab_alloc_node mm/slub.c:3854 [inline]
__do_kmalloc_node mm/slub.c:3984 [inline]
__kmalloc_node_track_caller+0x367/0x470 mm/slub.c:4005
kstrdup+0x3c/0x70 mm/util.c:62
kstrdup_const+0x5f/0x70 mm/util.c:85
kvasprintf_const+0x10b/0x190 lib/kasprintf.c:48
kobject_set_name_vargs+0x5a/0x130 lib/kobject.c:272
kobject_add_varg lib/kobject.c:366 [inline]
kobject_init_and_add+0xe8/0x190 lib/kobject.c:455
locate_module_kobject+0xef/0x190 kernel/params.c:781
kernel_add_sysfs_param kernel/params.c:808 [inline]
param_sysfs_builtin kernel/params.c:856 [inline]
param_sysfs_builtin_init+0x25f/0x450 kernel/params.c:990
do_one_initcall+0x128/0x680 init/main.c:1236
page last free pid 3062 tgid 3062 stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x51f/0xb10 mm/page_alloc.c:2390
free_unref_page+0x33/0x3b0 mm/page_alloc.c:2530
mm_free_pgd kernel/fork.c:799 [inline]
__mmdrop+0xd5/0x470 kernel/fork.c:915
mmdrop include/linux/sched/mm.h:54 [inline]
__mmput+0x40a/0x4d0 kernel/fork.c:1352
mmput+0x62/0x70 kernel/fork.c:1363
free_bprm+0x143/0x3e0 fs/exec.c:1490
kernel_execve+0x3e6/0x4e0 fs/exec.c:2036
call_usermodehelper_exec_async+0x252/0x4c0 kernel/umh.c:110
ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
Memory state around the buggy address:
ffff888028893f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888028894000: 07 fc fc fc 07 fc fc fc fa fc fc fc 05 fc fc fc
>ffff888028894080: 04 fc fc fc fb fc fc fc fb fc fc fc 06 fc fc fc
^
ffff888028894100: 06 fc fc fc fb fc fc fc 00 fc fc fc 00 fc fc fc
ffff888028894180: fb fc fc fc 04 fc fc fc 04 fc fc fc fb fc fc fc
==================================================================---
This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at [email protected].
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot
syzbotFor archival purposes, forwarding an incoming command email to [email protected].
For archival purposes, forwarding an incoming command email to [email protected].
***
Subject: [net?] KASAN: slab-out-of-bounds Read in dns_resolver_preparse
Author: [email protected]
please test slab-out-of-bounds Read in dns_resolver_preparse
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 48e8992e33ab
security/keys/keyctl.c +1 -1
@@ -83,7 +83,7 @@ SYSCALL_DEFINE5(add_key, const char __user *, _type,long ret; ret = -EINVAL ; -if (plen >1024 *1024 -1 ) +if (plen >1024 *1024 -1 || plen <48 ) goto error;/* draw all the data into kernel space */
syzbot
syzbotFor archival purposes, forwarding an incoming command email to [email protected].
For archival purposes, forwarding an incoming command email to [email protected].
***
Subject: [net?] KASAN: slab-out-of-bounds Read in dns_resolver_preparse
Author: [email protected]
please test slab-out-of-bounds Read in dns_resolver_preparse
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 48e8992e33ab
net/dns_resolver/dns_key.c +1 -1
@@ -104,7 +104,7 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)if (data[0 ] ==0 ) {/* It may be a server list. */ -if (datalen <=sizeof (*bin)) +if (datalen <=sizeof (*v1))return -EINVAL ; bin = (const struct dns_payload_header *)data;
PATCH 1/1 keys/dns: datalen must greater than sizeof(*v1)
In reply to syzbotbin will be forcibly converted to "struct dns_server_list_v1_header *", so it is necessary to compare datalen with sizeof(*v1).
--- net/dns_resolver/dns_key.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
net/dns_resolver/dns_key.c +1 -1
@@ -104,7 +104,7 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)if (data[0 ] ==0 ) {/* It may be a server list. */ -if (datalen <=sizeof (*bin)) +if (datalen <=sizeof (*v1))return -EINVAL ; bin = (const struct dns_payload_header *)data;
PATCH v2 1/1 keys/dns: fix slab-out-of-bounds in dns_resolver_preparse
bin will be forcibly converted to "struct dns_server_list_v1_header *", so it is necessary to compare datalen with sizeof(*v1).
--- net/dns_resolver/dns_key.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
net/dns_resolver/dns_key.c +1 -1
@@ -104,7 +104,7 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)if (data[0 ] ==0 ) {/* It may be a server list. */ -if (datalen <=sizeof (*bin)) +if (datalen <=sizeof (*v1))return -EINVAL ; bin = (const struct dns_payload_header *)data;
Signature · 1 line
2.43.0
Re: [PATCH V2 next] keys/dns: fix slab-out-of-bounds in dns_resolver_preparse
Quoted 9 lines · Edward Adam Davis
bin will be forcibly converted to "struct
dns_server_list_v1_header*", so it is necessary to compare datalen withsizeof(*v1).Fixes b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")Reported-and-tested-by [email protected]Signed-off-by Edward Adam Davis <[email protected]>--- net/dns_resolver/dns_key.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
This change looks correct to me.
And I agree that it addresses a problem introduced by the cited commit. I also note that it depends on the cited commit, which is not present in net.
Re: [PATCH next] keys/dns: datalen must greater than sizeof(*v1)
In reply to Edward Adam DavisQuoted 15 lines · Edward Adam Davis
bin will be forcibly converted to "struct
dns_server_list_v1_header*", so it is necessary to compare datalen withsizeof(*v1).Fixes b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")Reported-and-tested-by [email protected]Signed-off-by Edward Adam Davis <[email protected]>--- net/dns_resolver/dns_key.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)net/dns_resolver/dns_key.c +0
-0
net/dns_resolver/dns_key.c dns_resolver_preparse(struct key_preparsed_payload *prep) · line 110
Quoted 8 lines
net/dns_resolver/dns_key.c +1
-1@@ -104,7 +104,7 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)if (data[0 ] ==0 ) {/* It may be a server list. */ -if (datalen <=sizeof (*bin)) +if (datalen <=sizeof (*v1))return -EINVAL ; bin = (const struct dns_payload_header *)data;
BR, Jarkko
David Howells
maintainer#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
net/dns_resolver/dns_key.c +9 -10
@@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;static int dns_resolver_preparse (struct key_preparsed_payload *prep) { -const struct dns_server_list_v1_header *v1; -const struct dns_payload_header *bin;struct user_key_payload *upayload;unsigned long derrno;int ret;
@@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)return -EINVAL ;if (data[0 ] ==0 ) { +const struct dns_server_list_v1_header *v1; +/* It may be a server list. */ -if (datalen <=sizeof (*bin)) +if (datalen <=sizeof (*v1))return -EINVAL ; - bin = (const struct dns_payload_header *)data; -kenter ("[%u,%u],%u" , bin->content, bin->version, datalen); -if (bin->content !=DNS_PAYLOAD_IS_SERVER_LIST ) { + v1 = (const struct dns_server_list_v1_header *)data; +kenter ("[%u,%u],%u" , v1->hdr.content, v1->hdr.version, datalen); +if (v1->hdr.content !=DNS_PAYLOAD_IS_SERVER_LIST ) {pr_warn_ratelimited ("dns_resolver: Unsupported content type (%u)\n" , - bin->content); + v1->hdr.content);return -EINVAL ; } -if (bin->version !=1 ) { +if (v1->hdr.version !=1 ) {pr_warn_ratelimited ("dns_resolver: Unsupported server list version (%u)\n" , - bin->version); + v1->hdr.version);return -EINVAL ; } - v1 = (const struct dns_server_list_v1_header *)bin;if ((v1->status !=DNS_LOOKUP_GOOD && v1->status !=DNS_LOOKUP_GOOD_WITH_BAD )) {if (prep->expiry ==TIME64_MAX )
syzbot
syzbotwant either no args or 2 args (repo, branch), got 5
Quoted 1 line
#syz test:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
want either no args or 2 args (repo, branch), got 5
Quoted 52 lines
net/dns_resolver/dns_key.c +9
-10@@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;static int dns_resolver_preparse (struct key_preparsed_payload *prep) { -const struct dns_server_list_v1_header *v1; -const struct dns_payload_header *bin;struct user_key_payload *upayload;unsigned long derrno;int ret;@@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)return -EINVAL ;if (data[0 ] ==0 ) { +const struct dns_server_list_v1_header *v1; +/* It may be a server list. */ -if (datalen <=sizeof (*bin)) +if (datalen <=sizeof (*v1))return -EINVAL ; - bin = (const struct dns_payload_header *)data; -kenter ("[%u,%u],%u" , bin->content, bin->version, datalen); -if (bin->content !=DNS_PAYLOAD_IS_SERVER_LIST ) { + v1 = (const struct dns_server_list_v1_header *)data; +kenter ("[%u,%u],%u" , v1->hdr.content, v1->hdr.version, datalen); +if (v1->hdr.content !=DNS_PAYLOAD_IS_SERVER_LIST ) {pr_warn_ratelimited ("dns_resolver: Unsupported content type (%u)\n" , - bin->content); + v1->hdr.content);return -EINVAL ; } -if (bin->version !=1 ) { +if (v1->hdr.version !=1 ) {pr_warn_ratelimited ("dns_resolver: Unsupported server list version (%u)\n" , - bin->version); + v1->hdr.version);return -EINVAL ; } - v1 = (const struct dns_server_list_v1_header *)bin;if ((v1->status !=DNS_LOOKUP_GOOD && v1->status !=DNS_LOOKUP_GOOD_WITH_BAD )) {if (prep->expiry ==TIME64_MAX )
David Howells
maintainer#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
net/dns_resolver/dns_key.c +9 -10
@@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;static int dns_resolver_preparse (struct key_preparsed_payload *prep) { -const struct dns_server_list_v1_header *v1; -const struct dns_payload_header *bin;struct user_key_payload *upayload;unsigned long derrno;int ret;
@@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)return -EINVAL ;if (data[0 ] ==0 ) { +const struct dns_server_list_v1_header *v1; +/* It may be a server list. */ -if (datalen <=sizeof (*bin)) +if (datalen <=sizeof (*v1))return -EINVAL ; - bin = (const struct dns_payload_header *)data; -kenter ("[%u,%u],%u" , bin->content, bin->version, datalen); -if (bin->content !=DNS_PAYLOAD_IS_SERVER_LIST ) { + v1 = (const struct dns_server_list_v1_header *)data; +kenter ("[%u,%u],%u" , v1->hdr.content, v1->hdr.version, datalen); +if (v1->hdr.content !=DNS_PAYLOAD_IS_SERVER_LIST ) {pr_warn_ratelimited ("dns_resolver: Unsupported content type (%u)\n" , - bin->content); + v1->hdr.content);return -EINVAL ; } -if (bin->version !=1 ) { +if (v1->hdr.version !=1 ) {pr_warn_ratelimited ("dns_resolver: Unsupported server list version (%u)\n" , - bin->version); + v1->hdr.version);return -EINVAL ; } - v1 = (const struct dns_server_list_v1_header *)bin;if ((v1->status !=DNS_LOOKUP_GOOD && v1->status !=DNS_LOOKUP_GOOD_WITH_BAD )) {if (prep->expiry ==TIME64_MAX )
syzbot
syzbotsyzbot has tested the proposed patch and the reproducer did not trigger any issue:
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Tested on:
commit: 3f82f1c3 Merge tag 'x86-urgent-2023-12-23' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=132be7e9e80000 kernel config: https://syzkaller.appspot.com/x/.config?x=9f7c7b3fa354ead9 dashboard link: https://syzkaller.appspot.com/bug?extid=94bbb75204a05da3d89f compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 patch: https://syzkaller.appspot.com/x/patch.diff?x=15ef6e26e80000
Note: testing is done by a robot and is best-effort only.