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Josh Law
20909df31b
commit 8cdf30813e upstream.
The ts_kmp algorithm stores its prefix_tbl[] table and pattern in a single
allocation sized from the pattern length. If the prefix_tbl[] size
calculation wraps, the resulting allocation can be too small and
subsequent pattern copies can overflow it.
Fix this by rejecting zero-length patterns and by using overflow helpers
before calculating the combined allocation size.
This fixes a potential heap overflow. The pattern length calculation can
wrap during a size_t addition, leading to an undersized allocation.
Because the textsearch library is reachable from userspace via Netfilter's
xt_string module, this is a security risk that should be backported to LTS
kernels.
Link: https://lkml.kernel.org/r/20260308202028.2889285-2-objecting@objecting.org
Signed-off-by: Josh Law <objecting@objecting.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>