From: Alan Stern <stern@rowland.harvard.edu> mainline inclusion from mainline-v6.17-rc1 commit a6b87bfc2ab5bccb7ad953693c85d9062aef3fdd category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/9186 CVE: CVE-2025-38556 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- Testing by the syzbot fuzzer showed that the HID core gets a shift-out-of-bounds exception when it tries to convert a 32-bit quantity to a 0-bit quantity. Ideally this should never occur, but there are buggy devices and some might have a report field with size set to zero; we shouldn't reject the report or the device just because of that. Instead, harden the s32ton() routine so that it returns a reasonable result instead of crashing when it is called with the number of bits set to 0 -- the same as what snto32() does. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: syzbot+b63d677d63bcac06cf90@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-usb/68753a08.050a0220.33d347.0008.GAE@google.c... Tested-by: syzbot+b63d677d63bcac06cf90@syzkaller.appspotmail.com Fixes: dde5845a529f ("[PATCH] Generic HID layer - code split") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/613a66cd-4309-4bce-a4f7-2905f9bce0c9@rowland.harvar... Signed-off-by: Benjamin Tissoires <bentiss@kernel.org> Conflicts: drivers/hid/hid-core.c [Only context conflict because of commit c653ffc283404 is not applied] Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com> --- drivers/hid/hid-core.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 3094c33bb8f9..a602f572d458 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -1347,7 +1347,12 @@ EXPORT_SYMBOL_GPL(hid_snto32); static u32 s32ton(__s32 value, unsigned n) { - s32 a = value >> (n - 1); + s32 a; + + if (!value || !n) + return 0; + + a = value >> (n - 1); if (a && a != -1) return value < 0 ? 1 << (n - 1) : (1 << (n - 1)) - 1; return value & ((1 << n) - 1); -- 2.22.0