4.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit d63967e475ae10f286dbd35e189cb241e0b1f284 ]
Since capi_ioctl() copies 64 bytes after calling capi20_get_manufacturer() we need to ensure to not leak information to user.
BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32 CPU: 0 PID: 11245 Comm: syz-executor633 Not tainted 4.20.0-rc7+ #2 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x173/0x1d0 lib/dump_stack.c:113 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613 kmsan_internal_check_memory+0x9d4/0xb00 mm/kmsan/kmsan.c:704 kmsan_copy_to_user+0xab/0xc0 mm/kmsan/kmsan_hooks.c:601 _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32 capi_ioctl include/linux/uaccess.h:177 [inline] capi_unlocked_ioctl+0x1a0b/0x1bf0 drivers/isdn/capi/capi.c:939 do_vfs_ioctl+0xebd/0x2bf0 fs/ioctl.c:46 ksys_ioctl fs/ioctl.c:713 [inline] __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl+0x1da/0x270 fs/ioctl.c:718 __x64_sys_ioctl+0x4a/0x70 fs/ioctl.c:718 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x440019 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffdd4659fb8 EFLAGS: 00000213 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440019 RDX: 0000000020000080 RSI: 00000000c0044306 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000213 R12: 00000000004018a0 R13: 0000000000401930 R14: 0000000000000000 R15: 0000000000000000
Local variable description: ----data.i@capi_unlocked_ioctl Variable was created at: capi_ioctl drivers/isdn/capi/capi.c:747 [inline] capi_unlocked_ioctl+0x82/0x1bf0 drivers/isdn/capi/capi.c:939 do_vfs_ioctl+0xebd/0x2bf0 fs/ioctl.c:46
Bytes 12-63 of 64 are uninitialized Memory access of size 64 starts at ffff88807ac5fce8 Data copied to user address 0000000020000080
Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: Karsten Keil isdn@linux-pingi.de Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/isdn/capi/kcapi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/isdn/capi/kcapi.c +++ b/drivers/isdn/capi/kcapi.c @@ -851,7 +851,7 @@ u16 capi20_get_manufacturer(u32 contr, u u16 ret;
if (contr == 0) { - strlcpy(buf, capi_manufakturer, CAPI_MANUFACTURER_LEN); + strncpy(buf, capi_manufakturer, CAPI_MANUFACTURER_LEN); return CAPI_NOERROR; }
@@ -859,7 +859,7 @@ u16 capi20_get_manufacturer(u32 contr, u
ctr = get_capi_ctr_by_nr(contr); if (ctr && ctr->state == CAPI_CTR_RUNNING) { - strlcpy(buf, ctr->manu, CAPI_MANUFACTURER_LEN); + strncpy(buf, ctr->manu, CAPI_MANUFACTURER_LEN); ret = CAPI_NOERROR; } else ret = CAPI_REGNOTINSTALLED;