commit 82d12088c297fa1cef670e1718b3d24f414c23f7 upstream.
Discovered by Atuin - Automated Vulnerability Discovery Engine.
In ac_ioctl, the validation of IndexCard and the check for a valid
RamIO pointer are skipped when cmd is 6. However, the function
unconditionally executes readb(apbs[IndexCard].RamIO + VERS) at the
end.
If cmd is 6, IndexCard may reference a board that does not exist
(where RamIO is NULL), leading to a NULL pointer dereference.
Fix this by skipping the readb access when cmd is 6, as this
command is a global information query and does not target a specific
board context.
Signed-off-by: Tianchu Chen <flynnnchen@tencent.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: stable <stable@kernel.org>
Link: https://patch.msgid.link/20251128155323.a786fde92ebb926cbe96fcb1@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
f83e3e9f89