CVE-2022-49148

In the Linux kernel, the following vulnerability has been resolved:

watch_queue: Free the page array when watch_queue is dismantled

Commit 7ea1a0124b6d (watch_queue: Free the alloc bitmap when the watch_queue is torn down) took care of the bitmap, but not the page array.

BUG: memory leak unreferenced object 0xffff88810d9bc140 (size 32): comm syz-executor335, pid 3603, jiffies 4294946994 (age 12.840s) hex dump (first 32 bytes): 40 a7 40 04 00 ea ff ff 00 00 00 00 00 00 00 00 @.@…………. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ……………. backtrace: kmalloc_array include/linux/slab.h:621 [inline] kcalloc include/linux/slab.h:652 [inline] watch_queue_set_size+0x12f/0x2e0 kernel/watch_queue.c:251 pipe_ioctl+0x82/0x140 fs/pipe.c:632 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline]

Weakness 

The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

Affected Software 

Potential Mitigations 

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References  

• https://git.kernel.org/stable/c/375cd2536494cfbcdda84ae8b3e35bf19d0250b9
• https://git.kernel.org/stable/c/3963a5d1ff75585bddf0c3a918566a6be09d7520
• https://git.kernel.org/stable/c/4913daecd04addb41bc96a9175a885e1c19862a8
• https://git.kernel.org/stable/c/7169f60110915c8b53bffd43741fa020a75eb87a
• https://git.kernel.org/stable/c/b490207017ba237d97b735b2aa66dc241ccd18f5