* [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing
@ 2022-02-04 23:58 Stanislav Fomichev
2022-02-04 23:58 ` [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test_finish " Stanislav Fomichev
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Stanislav Fomichev @ 2022-02-04 23:58 UTC (permalink / raw)
To: netdev, bpf
Cc: ast, daniel, andrii, Stanislav Fomichev, Lorenzo Bianconi, syzbot
When kattr->test.data_size_in > INT_MAX, signed min_t will assign
negative value to data_len. This negative value then gets passed
over to copy_from_user where it is converted to (big) unsigned.
Use unsigned min_t to avoid this overflow.
usercopy: Kernel memory overwrite attempt detected to wrapped address
(offset 0, size 18446612140539162846)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:102!
invalid opcode: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 0 PID: 3781 Comm: syz-executor226 Not tainted 4.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:usercopy_abort+0xbd/0xbf mm/usercopy.c:102
RSP: 0018:ffff8801e9703a38 EFLAGS: 00010286
RAX: 000000000000006c RBX: ffffffff84fc7040 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff816560a2 RDI: ffffed003d2e0739
RBP: ffff8801e9703a90 R08: 000000000000006c R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff84fc73a0
R13: ffffffff84fc7180 R14: ffffffff84fc7040 R15: ffffffff84fc7040
FS: 00007f54e0bec300(0000) GS:ffff8801f6600000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000280 CR3: 00000001e90ea000 CR4: 00000000003426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
check_bogus_address mm/usercopy.c:155 [inline]
__check_object_size mm/usercopy.c:263 [inline]
__check_object_size.cold+0x8c/0xad mm/usercopy.c:253
check_object_size include/linux/thread_info.h:112 [inline]
check_copy_size include/linux/thread_info.h:143 [inline]
copy_from_user include/linux/uaccess.h:142 [inline]
bpf_prog_test_run_xdp+0xe57/0x1240 net/bpf/test_run.c:989
bpf_prog_test_run kernel/bpf/syscall.c:3377 [inline]
__sys_bpf+0xdf2/0x4a50 kernel/bpf/syscall.c:4679
SYSC_bpf kernel/bpf/syscall.c:4765 [inline]
SyS_bpf+0x26/0x50 kernel/bpf/syscall.c:4763
do_syscall_64+0x21a/0x3e0 arch/x86/entry/common.c:305
entry_SYSCALL_64_after_hwframe+0x46/0xbb
Cc: Lorenzo Bianconi <lorenzo@kernel.org>
Fixes: 1c1949982524 ("bpf: introduce frags support to bpf_prog_test_run_xdp()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
net/bpf/test_run.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 0220b0822d77..5819a7a5e3c6 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -960,7 +960,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
while (size < kattr->test.data_size_in) {
struct page *page;
skb_frag_t *frag;
- int data_len;
+ u32 data_len;
if (sinfo->nr_frags == MAX_SKB_FRAGS) {
ret = -ENOMEM;
@@ -976,7 +976,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
frag = &sinfo->frags[sinfo->nr_frags++];
__skb_frag_set_page(frag, page);
- data_len = min_t(int, kattr->test.data_size_in - size,
+ data_len = min_t(u32, kattr->test.data_size_in - size,
PAGE_SIZE);
skb_frag_size_set(frag, data_len);
--
2.35.0.263.gb82422642f-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test_finish frags parsing
2022-02-04 23:58 [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing Stanislav Fomichev
@ 2022-02-04 23:58 ` Stanislav Fomichev
2022-02-07 17:44 ` Yonghong Song
2022-02-07 13:53 ` [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp " Lorenzo Bianconi
` (2 subsequent siblings)
3 siblings, 1 reply; 6+ messages in thread
From: Stanislav Fomichev @ 2022-02-04 23:58 UTC (permalink / raw)
To: netdev, bpf; +Cc: ast, daniel, andrii, Stanislav Fomichev, Lorenzo Bianconi
This place also uses signed min_t and passes this singed int to
copy_to_user (which accepts unsigned argument). I don't think
there is an issue, but let's be consistent.
Cc: Lorenzo Bianconi <lorenzo@kernel.org>
Fixes: 7855e0db150ad ("bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
net/bpf/test_run.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 5819a7a5e3c6..cb150f756f3d 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -154,7 +154,8 @@ static int bpf_test_finish(const union bpf_attr *kattr,
goto out;
if (sinfo) {
- int i, offset = len, data_len;
+ int i, offset = len;
+ u32 data_len;
for (i = 0; i < sinfo->nr_frags; i++) {
skb_frag_t *frag = &sinfo->frags[i];
@@ -164,7 +165,7 @@ static int bpf_test_finish(const union bpf_attr *kattr,
break;
}
- data_len = min_t(int, copy_size - offset,
+ data_len = min_t(u32, copy_size - offset,
skb_frag_size(frag));
if (copy_to_user(data_out + offset,
--
2.35.0.263.gb82422642f-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing
2022-02-04 23:58 [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing Stanislav Fomichev
2022-02-04 23:58 ` [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test_finish " Stanislav Fomichev
@ 2022-02-07 13:53 ` Lorenzo Bianconi
2022-02-07 17:23 ` Yonghong Song
2022-02-08 2:40 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 6+ messages in thread
From: Lorenzo Bianconi @ 2022-02-07 13:53 UTC (permalink / raw)
To: Stanislav Fomichev; +Cc: netdev, bpf, ast, daniel, andrii, syzbot
[-- Attachment #1: Type: text/plain, Size: 3503 bytes --]
> When kattr->test.data_size_in > INT_MAX, signed min_t will assign
> negative value to data_len. This negative value then gets passed
> over to copy_from_user where it is converted to (big) unsigned.
>
> Use unsigned min_t to avoid this overflow.
Thx for fixing it.
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
>
> usercopy: Kernel memory overwrite attempt detected to wrapped address
> (offset 0, size 18446612140539162846)!
> ------------[ cut here ]------------
> kernel BUG at mm/usercopy.c:102!
> invalid opcode: 0000 [#1] SMP KASAN
> Modules linked in:
> CPU: 0 PID: 3781 Comm: syz-executor226 Not tainted 4.15.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:usercopy_abort+0xbd/0xbf mm/usercopy.c:102
> RSP: 0018:ffff8801e9703a38 EFLAGS: 00010286
> RAX: 000000000000006c RBX: ffffffff84fc7040 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffffffff816560a2 RDI: ffffed003d2e0739
> RBP: ffff8801e9703a90 R08: 000000000000006c R09: 0000000000000001
> R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff84fc73a0
> R13: ffffffff84fc7180 R14: ffffffff84fc7040 R15: ffffffff84fc7040
> FS: 00007f54e0bec300(0000) GS:ffff8801f6600000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020000280 CR3: 00000001e90ea000 CR4: 00000000003426f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> check_bogus_address mm/usercopy.c:155 [inline]
> __check_object_size mm/usercopy.c:263 [inline]
> __check_object_size.cold+0x8c/0xad mm/usercopy.c:253
> check_object_size include/linux/thread_info.h:112 [inline]
> check_copy_size include/linux/thread_info.h:143 [inline]
> copy_from_user include/linux/uaccess.h:142 [inline]
> bpf_prog_test_run_xdp+0xe57/0x1240 net/bpf/test_run.c:989
> bpf_prog_test_run kernel/bpf/syscall.c:3377 [inline]
> __sys_bpf+0xdf2/0x4a50 kernel/bpf/syscall.c:4679
> SYSC_bpf kernel/bpf/syscall.c:4765 [inline]
> SyS_bpf+0x26/0x50 kernel/bpf/syscall.c:4763
> do_syscall_64+0x21a/0x3e0 arch/x86/entry/common.c:305
> entry_SYSCALL_64_after_hwframe+0x46/0xbb
>
> Cc: Lorenzo Bianconi <lorenzo@kernel.org>
> Fixes: 1c1949982524 ("bpf: introduce frags support to bpf_prog_test_run_xdp()")
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
> ---
> net/bpf/test_run.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index 0220b0822d77..5819a7a5e3c6 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -960,7 +960,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
> while (size < kattr->test.data_size_in) {
> struct page *page;
> skb_frag_t *frag;
> - int data_len;
> + u32 data_len;
>
> if (sinfo->nr_frags == MAX_SKB_FRAGS) {
> ret = -ENOMEM;
> @@ -976,7 +976,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
> frag = &sinfo->frags[sinfo->nr_frags++];
> __skb_frag_set_page(frag, page);
>
> - data_len = min_t(int, kattr->test.data_size_in - size,
> + data_len = min_t(u32, kattr->test.data_size_in - size,
> PAGE_SIZE);
> skb_frag_size_set(frag, data_len);
>
> --
> 2.35.0.263.gb82422642f-goog
>
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing
2022-02-04 23:58 [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing Stanislav Fomichev
2022-02-04 23:58 ` [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test_finish " Stanislav Fomichev
2022-02-07 13:53 ` [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp " Lorenzo Bianconi
@ 2022-02-07 17:23 ` Yonghong Song
2022-02-08 2:40 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 6+ messages in thread
From: Yonghong Song @ 2022-02-07 17:23 UTC (permalink / raw)
To: Stanislav Fomichev, netdev, bpf
Cc: ast, daniel, andrii, Lorenzo Bianconi, syzbot
On 2/4/22 3:58 PM, Stanislav Fomichev wrote:
> When kattr->test.data_size_in > INT_MAX, signed min_t will assign
> negative value to data_len. This negative value then gets passed
> over to copy_from_user where it is converted to (big) unsigned.
>
> Use unsigned min_t to avoid this overflow.
>
> usercopy: Kernel memory overwrite attempt detected to wrapped address
> (offset 0, size 18446612140539162846)!
> ------------[ cut here ]------------
> kernel BUG at mm/usercopy.c:102!
> invalid opcode: 0000 [#1] SMP KASAN
> Modules linked in:
> CPU: 0 PID: 3781 Comm: syz-executor226 Not tainted 4.15.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> RIP: 0010:usercopy_abort+0xbd/0xbf mm/usercopy.c:102
> RSP: 0018:ffff8801e9703a38 EFLAGS: 00010286
> RAX: 000000000000006c RBX: ffffffff84fc7040 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffffffff816560a2 RDI: ffffed003d2e0739
> RBP: ffff8801e9703a90 R08: 000000000000006c R09: 0000000000000001
> R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff84fc73a0
> R13: ffffffff84fc7180 R14: ffffffff84fc7040 R15: ffffffff84fc7040
> FS: 00007f54e0bec300(0000) GS:ffff8801f6600000(0000)
> knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020000280 CR3: 00000001e90ea000 CR4: 00000000003426f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> check_bogus_address mm/usercopy.c:155 [inline]
> __check_object_size mm/usercopy.c:263 [inline]
> __check_object_size.cold+0x8c/0xad mm/usercopy.c:253
> check_object_size include/linux/thread_info.h:112 [inline]
> check_copy_size include/linux/thread_info.h:143 [inline]
> copy_from_user include/linux/uaccess.h:142 [inline]
> bpf_prog_test_run_xdp+0xe57/0x1240 net/bpf/test_run.c:989
> bpf_prog_test_run kernel/bpf/syscall.c:3377 [inline]
> __sys_bpf+0xdf2/0x4a50 kernel/bpf/syscall.c:4679
> SYSC_bpf kernel/bpf/syscall.c:4765 [inline]
> SyS_bpf+0x26/0x50 kernel/bpf/syscall.c:4763
> do_syscall_64+0x21a/0x3e0 arch/x86/entry/common.c:305
> entry_SYSCALL_64_after_hwframe+0x46/0xbb
>
> Cc: Lorenzo Bianconi <lorenzo@kernel.org>
> Fixes: 1c1949982524 ("bpf: introduce frags support to bpf_prog_test_run_xdp()")
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Yonghong Song <yhs@fb.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test_finish frags parsing
2022-02-04 23:58 ` [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test_finish " Stanislav Fomichev
@ 2022-02-07 17:44 ` Yonghong Song
0 siblings, 0 replies; 6+ messages in thread
From: Yonghong Song @ 2022-02-07 17:44 UTC (permalink / raw)
To: Stanislav Fomichev, netdev, bpf; +Cc: ast, daniel, andrii, Lorenzo Bianconi
On 2/4/22 3:58 PM, Stanislav Fomichev wrote:
> This place also uses signed min_t and passes this singed int to
> copy_to_user (which accepts unsigned argument). I don't think
> there is an issue, but let's be consistent.
>
> Cc: Lorenzo Bianconi <lorenzo@kernel.org>
> Fixes: 7855e0db150ad ("bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature")
> Signed-off-by: Stanislav Fomichev <sdf@google.com>
Agreed that there is no actual issue as the 'copy_size' should be small
here (<= maximum skb total packet size). I tried to add
-Wsign-conversion to kernel compilation and saw tons of warnings. I guess
we have to deal with case by case then.
Acked-by: Yonghong Song <yhs@fb.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing
2022-02-04 23:58 [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing Stanislav Fomichev
` (2 preceding siblings ...)
2022-02-07 17:23 ` Yonghong Song
@ 2022-02-08 2:40 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 6+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-02-08 2:40 UTC (permalink / raw)
To: Stanislav Fomichev; +Cc: netdev, bpf, ast, daniel, andrii, lorenzo, syzkaller
Hello:
This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:
On Fri, 4 Feb 2022 15:58:48 -0800 you wrote:
> When kattr->test.data_size_in > INT_MAX, signed min_t will assign
> negative value to data_len. This negative value then gets passed
> over to copy_from_user where it is converted to (big) unsigned.
>
> Use unsigned min_t to avoid this overflow.
>
> usercopy: Kernel memory overwrite attempt detected to wrapped address
> (offset 0, size 18446612140539162846)!
>
> [...]
Here is the summary with links:
- [bpf-next,1/2] bpf: test_run: fix overflow in xdp frags parsing
https://git.kernel.org/bpf/bpf-next/c/9d63b59d1e9d
- [bpf-next,2/2] bpf: test_run: fix overflow in bpf_test_finish frags parsing
https://git.kernel.org/bpf/bpf-next/c/5d1e9f437df5
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 6+ messages in thread
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2022-02-04 23:58 [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp frags parsing Stanislav Fomichev
2022-02-04 23:58 ` [PATCH bpf-next 2/2] bpf: test_run: fix overflow in bpf_test_finish " Stanislav Fomichev
2022-02-07 17:44 ` Yonghong Song
2022-02-07 13:53 ` [PATCH bpf-next 1/2] bpf: test_run: fix overflow in xdp " Lorenzo Bianconi
2022-02-07 17:23 ` Yonghong Song
2022-02-08 2:40 ` patchwork-bot+netdevbpf
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