| Message ID | 20210813151433.22493-1-paskripkin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 19d1532a187669ce86d5a2696eb7275310070793 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] net: 6pack: fix slab-out-of-bounds in decode_data | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/cc_maintainers | success | CCed 5 of 5 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 12 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
Great!
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
regards,
dan carpenter
On 8/14/21 12:09 AM, Dan Carpenter wrote: > Great! > > Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> > Thank you, Dan! With regards, Pavel Skripkin
Hello: This patch was applied to netdev/net.git (refs/heads/master): On Fri, 13 Aug 2021 18:14:33 +0300 you wrote: > Syzbot reported slab-out-of bounds write in decode_data(). > The problem was in missing validation checks. > > Syzbot's reproducer generated malicious input, which caused > decode_data() to be called a lot in sixpack_decode(). Since > rx_count_cooked is only 400 bytes and noone reported before, > that 400 bytes is not enough, let's just check if input is malicious > and complain about buffer overrun. > > [...] Here is the summary with links: - [v2] net: 6pack: fix slab-out-of-bounds in decode_data https://git.kernel.org/netdev/net/c/19d1532a1876 You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c index fcf3af76b6d7..8fe8887d506a 100644 --- a/drivers/net/hamradio/6pack.c +++ b/drivers/net/hamradio/6pack.c @@ -827,6 +827,12 @@ static void decode_data(struct sixpack *sp, unsigned char inbyte) return; } + if (sp->rx_count_cooked + 2 >= sizeof(sp->cooked_buf)) { + pr_err("6pack: cooked buffer overrun, data loss\n"); + sp->rx_count = 0; + return; + } + buf = sp->raw_buf; sp->cooked_buf[sp->rx_count_cooked++] = buf[0] | ((buf[1] << 2) & 0xc0);
Syzbot reported slab-out-of bounds write in decode_data(). The problem was in missing validation checks. Syzbot's reproducer generated malicious input, which caused decode_data() to be called a lot in sixpack_decode(). Since rx_count_cooked is only 400 bytes and noone reported before, that 400 bytes is not enough, let's just check if input is malicious and complain about buffer overrun. Fail log: ================================================================== BUG: KASAN: slab-out-of-bounds in drivers/net/hamradio/6pack.c:843 Write of size 1 at addr ffff888087c5544e by task kworker/u4:0/7 CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.6.0-rc3-syzkaller #0 ... Workqueue: events_unbound flush_to_ldisc Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 kasan_report+0x12/0x20 mm/kasan/common.c:641 __asan_report_store1_noabort+0x17/0x20 mm/kasan/generic_report.c:137 decode_data.part.0+0x23b/0x270 drivers/net/hamradio/6pack.c:843 decode_data drivers/net/hamradio/6pack.c:965 [inline] sixpack_decode drivers/net/hamradio/6pack.c:968 [inline] Reported-and-tested-by: syzbot+fc8cd9a673d4577fb2e4@syzkaller.appspotmail.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> --- Changes in v2: + 3 -> +2 (Reported by Dan Carpenter) --- drivers/net/hamradio/6pack.c | 6 ++++++ 1 file changed, 6 insertions(+)