Reject RSASSA-PSS params with negative salt length

The `salt_len` member in the struct is of type `ssize_t` because we use
negative values for special automatic salt lengths when generating
signatures.

Not checking this could lead to an integer overflow.  The value is assigned
to the `len` field of a chunk (`size_t`), which is further used in
calculations to check the padding structure and (if that is passed by a
matching crafted signature value) eventually a memcpy() that will result
in a segmentation fault.

Fixes: a22316520b91 ("signature-params: Add functions to parse/build ASN.1 RSASSA-PSS params")
Fixes: 7d6b81648b2d ("gmp: Add support for RSASSA-PSS signature verification")
Fixes: CVE-2021-41990
Signed-off-by: Daniil Baturin <daniil@baturin.org>

0 files changed, 0 insertions, 0 deletions