CVE-2023-53468ubifs: Fix memory leak in alloc_wbufs()

Official description

In the Linux kernel, the following vulnerability has been resolved: ubifs: Fix memory leak in alloc_wbufs() kmemleak reported a sequence of memory leaks, and show them as following: unreferenced object 0xffff8881575f8400 (size 1024): comm "mount", pid 19625, jiffies 4297119604 (age 20.383s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 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: [<ffffffff8176cecd>] __kmalloc+0x4d/0x150 [<ffffffffa0406b2b>] ubifs_mount+0x307b/0x7170 [ubifs] [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0 [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230 [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0 [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270 [<ffffffff83c14295>] do_syscall_64+0x35/0x80 [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 unreferenced object 0xffff8881798a6e00 (size 512): comm "mount", pid 19677, jiffies 4297121912 (age 37.816s) hex dump (first 32 bytes): 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk backtrace: [<ffffffff8176cecd>] __kmalloc+0x4d/0x150 [<ffffffffa0418342>] ubifs_wbuf_init+0x52/0x480 [ubifs] [<ffffffffa0406ca5>] ubifs_mount+0x31f5/0x7170 [ubifs] [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0 [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230 [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0 [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270 [<ffffffff83c14295>] do_syscall_64+0x35/0x80 [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0 The problem is that the ubifs_wbuf_init() returns an error in the loop which in the alloc_wbufs(), then the wbuf->buf and wbuf->inodes that were successfully alloced before are not freed. Fix it by adding error hanging path in alloc_wbufs() which frees the memory alloced before when ubifs_wbuf_init() returns an error.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/1f206002c6bc302bface871ef3f72c0bbcaa931c
• https://git.kernel.org/stable/c/bf50229494f0443b3f08427d7df63e5a7e2a796a
• https://git.kernel.org/stable/c/3e29634eb56e6547272fe4e568f63421f8b3b9fa
• https://git.kernel.org/stable/c/26ec45f1c504e15268383019df139d7983f1e67f
• https://git.kernel.org/stable/c/e11f36d3bc4d23f620754a948fe7b82b63dcb185
• https://git.kernel.org/stable/c/4a1ff3c5d04b9079b4f768d9a71b51c4af578dd2