Commit a1673e15 authored by Benjamin Kaduk's avatar Benjamin Kaduk Committed by Rich Salz
Browse files

Avoid negative array index in BIO_debug_callback() 



BIO_snprintf() can return -1 on truncation (and overflow as of commit
9cb17730).  Though neither can
realistically occur while printing a pointer and short fixed string into
a buffer of length 256, the analysis to confirm that this the case goes
somewhat far up the call chain, and not all static analyzers can
successfully follow the chain of logic.

It's easy enough to clamp the returned length to be nonnegative before
continuing, which appeases the static analyzer and does not harm the
subsequent code.

Reviewed-by: default avatarRichard Levitte <levitte@openssl.org>
Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
parent 80e8fdbe

crypto/bio/bio_cb.c

+3 −0
Original line number Diff line number Diff line
@@ -77,6 +77,9 @@ long BIO_debug_callback(BIO *bio, int cmd, const char *argp, 


    len = BIO_snprintf(buf,sizeof buf,"BIO[%p]: ",(void *)bio);



    /* Ignore errors and continue printing the other information. */

    if (len < 0)

        len = 0;

    p = buf + len;

    p_maxlen = sizeof(buf) - len;