title: block/rnbd-srv: Check for unlikely string overflow
description: In the Linux kernel, the following vulnerability has been resolved:
block/rnbd-srv: Check for unlikely string overflow
Since "dev_search_path" can technically be as large as PATH_MAX,
there was a risk of truncation when copying it and a second string
into "full_path" since it was also PATH_MAX sized. The W=1 builds were
reporting this warning:
drivers/block/rnbd/rnbd-srv.c: In function 'process_msg_open.isra':
drivers/block/rnbd/rnbd-srv.c:616:51: warning: '%s' directive output may be truncated writing up to 254 bytes into a region of size between 0 and 4095 [-Wformat-truncation=]
616 |                 snprintf(full_path, PATH_MAX, "%s/%s",
|                                                   ^~
In function 'rnbd_srv_get_full_path',
inlined from 'process_msg_open.isra' at drivers/block/rnbd/rnbd-srv.c:721:14: drivers/block/rnbd/rnbd-srv.c:616:17: note: 'snprintf' output between 2 and 4351 bytes into a destination of size 4096
616 |                 snprintf(full_path, PATH_MAX, "%s/%s",
|                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
617 |                          dev_search_path, dev_name);
|                          ~~~~~~~~~~~~~~~~~~~~~~~~~~
To fix this, unconditionally check for truncation (as was already done
for the case where "%SESSNAME%" was present).
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 1da177e4c3f4, lessThan: 95bc866c1197, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: f6abd5e17da3, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: af7bbdac8973, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 5b9ea86e6620, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: a2c6206f1810, status: affected, versionType: git
version: 1da177e4c3f4, lessThan: 9e4bf6a08d1e, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 5.10.210, lessThanOrEqual: 5.10.*, status: unaffected, versionType: custom
version: 5.15.149, lessThanOrEqual: 5.15.*, status: unaffected, versionType: custom
version: 6.1.77, lessThanOrEqual: 6.1.*, status: unaffected, versionType: custom
version: 6.6.16, lessThanOrEqual: 6.6.*, status: unaffected, versionType: custom
version: 6.7.4, lessThanOrEqual: 6.7.*, status: unaffected, versionType: custom
version: 6.8, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
