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| author | Badhri Jagan Sridharan <badhri@google.com> | 2023-05-08 21:44:43 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-13 18:45:56 +0900 |
| commit | d8f28269dd4bf9b55c3fb376ae31512730a96fce (patch) | |
| tree | b0511223ecc9faf510951a11963907fb12c5490b /drivers/usb | |
| parent | f22e9b67f19ccc73de1ae04375d4b30684e261f8 (diff) | |
| download | lwn-d8f28269dd4bf9b55c3fb376ae31512730a96fce.tar.gz lwn-d8f28269dd4bf9b55c3fb376ae31512730a96fce.zip | |
usb: typec: altmodes/displayport: fix pin_assignment_show
This patch fixes negative indexing of buf array in pin_assignment_show
when get_current_pin_assignments returns 0 i.e. no compatible pin
assignments are found.
BUG: KASAN: use-after-free in pin_assignment_show+0x26c/0x33c
...
Call trace:
dump_backtrace+0x110/0x204
dump_stack_lvl+0x84/0xbc
print_report+0x358/0x974
kasan_report+0x9c/0xfc
__do_kernel_fault+0xd4/0x2d4
do_bad_area+0x48/0x168
do_tag_check_fault+0x24/0x38
do_mem_abort+0x6c/0x14c
el1_abort+0x44/0x68
el1h_64_sync_handler+0x64/0xa4
el1h_64_sync+0x78/0x7c
pin_assignment_show+0x26c/0x33c
dev_attr_show+0x50/0xc0
Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable@vger.kernel.org
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230508214443.893436-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/typec/altmodes/displayport.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c index 8f3e884222ad..66de880b28d0 100644 --- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -516,6 +516,10 @@ static ssize_t pin_assignment_show(struct device *dev, mutex_unlock(&dp->lock); + /* get_current_pin_assignments can return 0 when no matching pin assignments are found */ + if (len == 0) + len++; + buf[len - 1] = '\n'; return len; } |