* [PATCH] exec: do not pass invalid pointer to kfree() from free_bprm()
@ 2024-11-05 11:13 Dmitry Antipov
2024-11-05 11:30 ` Mateusz Guzik
2024-11-05 13:35 ` Kirill A. Shutemov
0 siblings, 2 replies; 4+ messages in thread
From: Dmitry Antipov @ 2024-11-05 11:13 UTC (permalink / raw)
To: Tycho Andersen
Cc: Alexander Viro, Christian Brauner, Jan Kara, linux-fsdevel,
linux-mm, lvc-project, Dmitry Antipov,
syzbot+03e1af5c332f7e0eb84b
Syzbot has reported the following BUG:
kernel BUG at arch/x86/mm/physaddr.c:23!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 2 UID: 0 PID: 5869 Comm: repro Not tainted 6.12.0-rc5-next-20241101-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
RIP: 0010:__phys_addr+0x16a/0x170
Code: 40 a8 7a 8e 4c 89 f6 4c 89 fa e8 b1 4d aa 03 e9 45 ff ff ff e8 a7 1a 52 00 90 0f 0b e8 9f 1a 52 00 90 0f 0b e8 97 1a 52 00 90 <0f> 0b 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90002f7fda0 EFLAGS: 00010293
RAX: ffffffff8143a369 RBX: 000000007ffffff2 RCX: ffff888106df5640
RDX: 0000000000000000 RSI: 000000007ffffff2 RDI: 000000001fffffff
RBP: 1ffff11020df6d09 R08: ffffffff8143a305 R09: 1ffffffff203a1f6
R10: dffffc0000000000 R11: fffffbfff203a1f7 R12: dffffc0000000000
R13: fffffffffffffff2 R14: 000000007ffffff2 R15: ffff88802bc12d58
FS: 00007f01bd1a7600(0000) GS:ffff888062900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffffffffffff8 CR3: 0000000011f80000 CR4: 00000000000006f0
Call Trace:
<TASK>
? __die_body+0x5f/0xb0
? die+0x9e/0xc0
? do_trap+0x15a/0x3a0
? __phys_addr+0x16a/0x170
? do_error_trap+0x1dc/0x2c0
? __phys_addr+0x16a/0x170
? __pfx_do_error_trap+0x10/0x10
? handle_invalid_op+0x34/0x40
? __phys_addr+0x16a/0x170
? exc_invalid_op+0x38/0x50
? asm_exc_invalid_op+0x1a/0x20
? __phys_addr+0x105/0x170
? __phys_addr+0x169/0x170
? __phys_addr+0x16a/0x170
? free_bprm+0x2b5/0x300
kfree+0x71/0x420
? free_bprm+0x295/0x300
free_bprm+0x2b5/0x300
do_execveat_common+0x3ae/0x750
__x64_sys_execveat+0xc4/0xe0
do_syscall_64+0xf3/0x230
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f01bd0c36a9
Code: 5c c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 8b 0d 4f 37 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007fff034da398 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 0000000000403e00 RCX: 00007f01bd0c36a9
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000000001000 R09: 0000000000403e00
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff034da4b8
R13: 00007fff034da4c8 R14: 0000000000401050 R15: 00007f01bd1dca80
</TASK>
Since 'bprm_add_fixup_comm()' may set 'bprm->argv0' to 'ERR_PTR()',
errno-lookalike invalid pointer should not be passed to 'kfree()'.
Reported-by: syzbot+03e1af5c332f7e0eb84b@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=03e1af5c332f7e0eb84b
Fixes: 7afad450c998 ("exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case")
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
---
fs/exec.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/exec.c b/fs/exec.c
index ef18eb0ea5b4..df70ed8e36fe 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1496,7 +1496,8 @@ static void free_bprm(struct linux_binprm *bprm)
if (bprm->interp != bprm->filename)
kfree(bprm->interp);
kfree(bprm->fdpath);
- kfree(bprm->argv0);
+ if (!IS_ERR(bprm->argv0))
+ kfree(bprm->argv0);
kfree(bprm);
}
--
2.47.0
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] exec: do not pass invalid pointer to kfree() from free_bprm()
2024-11-05 11:13 [PATCH] exec: do not pass invalid pointer to kfree() from free_bprm() Dmitry Antipov
@ 2024-11-05 11:30 ` Mateusz Guzik
2024-11-05 13:08 ` Dmitry Antipov
2024-11-05 13:35 ` Kirill A. Shutemov
1 sibling, 1 reply; 4+ messages in thread
From: Mateusz Guzik @ 2024-11-05 11:30 UTC (permalink / raw)
To: Dmitry Antipov
Cc: Tycho Andersen, Alexander Viro, Christian Brauner, Jan Kara,
linux-fsdevel, linux-mm, lvc-project,
syzbot+03e1af5c332f7e0eb84b, vbabka
On Tue, Nov 05, 2024 at 02:13:44PM +0300, Dmitry Antipov wrote:
> Syzbot has reported the following BUG:
>
> kernel BUG at arch/x86/mm/physaddr.c:23!
[..]
> Since 'bprm_add_fixup_comm()' may set 'bprm->argv0' to 'ERR_PTR()',
> errno-lookalike invalid pointer should not be passed to 'kfree()'.
>
The specific instance aside, perhaps kfree could get patched up to
complain about it (when debug is enabled)?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] exec: do not pass invalid pointer to kfree() from free_bprm()
2024-11-05 11:30 ` Mateusz Guzik
@ 2024-11-05 13:08 ` Dmitry Antipov
0 siblings, 0 replies; 4+ messages in thread
From: Dmitry Antipov @ 2024-11-05 13:08 UTC (permalink / raw)
To: Mateusz Guzik
Cc: Tycho Andersen, Alexander Viro, Christian Brauner, Jan Kara,
linux-fsdevel, linux-mm, lvc-project,
syzbot+03e1af5c332f7e0eb84b, vbabka
On 11/5/24 2:30 PM, Mateusz Guzik wrote:
> The specific instance aside, perhaps kfree could get patched up to
> complain about it (when debug is enabled)?
Yes, it may be useful to have WARN_ON() from kfree() for such a case when debugging.
Dmitry
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] exec: do not pass invalid pointer to kfree() from free_bprm()
2024-11-05 11:13 [PATCH] exec: do not pass invalid pointer to kfree() from free_bprm() Dmitry Antipov
2024-11-05 11:30 ` Mateusz Guzik
@ 2024-11-05 13:35 ` Kirill A. Shutemov
1 sibling, 0 replies; 4+ messages in thread
From: Kirill A. Shutemov @ 2024-11-05 13:35 UTC (permalink / raw)
To: Dmitry Antipov
Cc: Tycho Andersen, Alexander Viro, Christian Brauner, Jan Kara,
linux-fsdevel, linux-mm, lvc-project,
syzbot+03e1af5c332f7e0eb84b
On Tue, Nov 05, 2024 at 02:13:44PM +0300, Dmitry Antipov wrote:
> Syzbot has reported the following BUG:
>
> kernel BUG at arch/x86/mm/physaddr.c:23!
> Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
> CPU: 2 UID: 0 PID: 5869 Comm: repro Not tainted 6.12.0-rc5-next-20241101-syzkaller #0
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
> RIP: 0010:__phys_addr+0x16a/0x170
> Code: 40 a8 7a 8e 4c 89 f6 4c 89 fa e8 b1 4d aa 03 e9 45 ff ff ff e8 a7 1a 52 00 90 0f 0b e8 9f 1a 52 00 90 0f 0b e8 97 1a 52 00 90 <0f> 0b 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
> RSP: 0018:ffffc90002f7fda0 EFLAGS: 00010293
> RAX: ffffffff8143a369 RBX: 000000007ffffff2 RCX: ffff888106df5640
> RDX: 0000000000000000 RSI: 000000007ffffff2 RDI: 000000001fffffff
> RBP: 1ffff11020df6d09 R08: ffffffff8143a305 R09: 1ffffffff203a1f6
> R10: dffffc0000000000 R11: fffffbfff203a1f7 R12: dffffc0000000000
> R13: fffffffffffffff2 R14: 000000007ffffff2 R15: ffff88802bc12d58
> FS: 00007f01bd1a7600(0000) GS:ffff888062900000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: fffffffffffffff8 CR3: 0000000011f80000 CR4: 00000000000006f0
> Call Trace:
> <TASK>
> ? __die_body+0x5f/0xb0
> ? die+0x9e/0xc0
> ? do_trap+0x15a/0x3a0
> ? __phys_addr+0x16a/0x170
> ? do_error_trap+0x1dc/0x2c0
> ? __phys_addr+0x16a/0x170
> ? __pfx_do_error_trap+0x10/0x10
> ? handle_invalid_op+0x34/0x40
> ? __phys_addr+0x16a/0x170
> ? exc_invalid_op+0x38/0x50
> ? asm_exc_invalid_op+0x1a/0x20
> ? __phys_addr+0x105/0x170
> ? __phys_addr+0x169/0x170
> ? __phys_addr+0x16a/0x170
> ? free_bprm+0x2b5/0x300
> kfree+0x71/0x420
> ? free_bprm+0x295/0x300
> free_bprm+0x2b5/0x300
> do_execveat_common+0x3ae/0x750
> __x64_sys_execveat+0xc4/0xe0
> do_syscall_64+0xf3/0x230
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f01bd0c36a9
> Code: 5c c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 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 8b 0d 4f 37 0d 00 f7 d8 64 89 01 48
> RSP: 002b:00007fff034da398 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
> RAX: ffffffffffffffda RBX: 0000000000403e00 RCX: 00007f01bd0c36a9
> RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000004
> RBP: 0000000000000001 R08: 0000000000001000 R09: 0000000000403e00
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff034da4b8
> R13: 00007fff034da4c8 R14: 0000000000401050 R15: 00007f01bd1dca80
> </TASK>
>
> Since 'bprm_add_fixup_comm()' may set 'bprm->argv0' to 'ERR_PTR()',
> errno-lookalike invalid pointer should not be passed to 'kfree()'.
>
> Reported-by: syzbot+03e1af5c332f7e0eb84b@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=03e1af5c332f7e0eb84b
> Fixes: 7afad450c998 ("exec: fix up /proc/pid/comm in the execveat(AT_EMPTY_PATH) case")
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
> ---
> fs/exec.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/exec.c b/fs/exec.c
> index ef18eb0ea5b4..df70ed8e36fe 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -1496,7 +1496,8 @@ static void free_bprm(struct linux_binprm *bprm)
> if (bprm->interp != bprm->filename)
> kfree(bprm->interp);
> kfree(bprm->fdpath);
> - kfree(bprm->argv0);
> + if (!IS_ERR(bprm->argv0))
> + kfree(bprm->argv0);
> kfree(bprm);
> }
It's better to avoid setting bprm->argv0 if strndup_user() fails.
diff --git a/fs/exec.c b/fs/exec.c
index ef18eb0ea5b4..9380e166eff5 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1504,6 +1504,7 @@ static int bprm_add_fixup_comm(struct linux_binprm *bprm,
struct user_arg_ptr argv)
{
const char __user *p = get_user_arg_ptr(argv, 0);
+ char *argv0;
/*
* If p == NULL, let's just fall back to fdpath.
@@ -1511,10 +1512,11 @@ static int bprm_add_fixup_comm(struct linux_binprm *bprm,
if (!p)
return 0;
- bprm->argv0 = strndup_user(p, MAX_ARG_STRLEN);
- if (IS_ERR(bprm->argv0))
- return PTR_ERR(bprm->argv0);
+ argv0 = strndup_user(p, MAX_ARG_STRLEN);
+ if (IS_ERR(argv0))
+ return PTR_ERR(argv0);
+ bprm->argv0 = argv0;
return 0;
}
--
Kiryl Shutsemau / Kirill A. Shutemov
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-12-05 15:25 UTC | newest]
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2024-11-05 11:13 [PATCH] exec: do not pass invalid pointer to kfree() from free_bprm() Dmitry Antipov
2024-11-05 11:30 ` Mateusz Guzik
2024-11-05 13:08 ` Dmitry Antipov
2024-11-05 13:35 ` Kirill A. Shutemov
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