Commit e3b35d2b authored by Vitezslav Cizek's avatar Vitezslav Cizek Committed by Matt Caswell
Browse files

openssl_strerror_r: Fix handling of GNU strerror_r 



GNU strerror_r may return either a pointer to a string that the function
stores in buf, or a pointer to some (immutable) static string in which case
buf is unused.

In such a case we need to set buf manually.

Reviewed-by: default avatarBernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/8371)
parent 68ad17e8

crypto/o_str.c

+22 −3
Original line number Diff line number Diff line
@@ -223,7 +223,26 @@ int openssl_strerror_r(int errnum, char *buf, size_t buflen) 
#if defined(_MSC_VER) && _MSC_VER>=1400

    return !strerror_s(buf, buflen, errnum);

#elif defined(_GNU_SOURCE)

    return strerror_r(errnum, buf, buflen) != NULL;

    char *err;



    /*

     * GNU strerror_r may not actually set buf.

     * It can return a pointer to some (immutable) static string in which case

     * buf is left unused.

     */

    err = strerror_r(errnum, buf, buflen);

    if (err == NULL)

        return 0;

    /*

     * If err is statically allocated, err != buf and we need to copy the data.

     * If err points somewhere inside buf, OPENSSL_strlcpy can handle this,

     * since src and dest are not annotated with __restrict and the function

     * reads src byte for byte and writes to dest.

     * If err == buf we do not have to copy anything.

     */

    if (err != buf)

        OPENSSL_strlcpy(buf, err, buflen);

    return 1;

#elif (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L) || \

      (defined(_XOPEN_SOURCE) && _XOPEN_SOURCE >= 600)

    /*
@@ -234,6 +253,7 @@ int openssl_strerror_r(int errnum, char *buf, size_t buflen) 
    return !strerror_r(errnum, buf, buflen);

#else

    char *err;



    /* Fall back to non-thread safe strerror()...its all we can do */

    if (buflen < 2)

        return 0;
@@ -241,8 +261,7 @@ int openssl_strerror_r(int errnum, char *buf, size_t buflen) 
    /* Can this ever happen? */

    if (err == NULL)

        return 0;

    strncpy(buf, err, buflen - 1);

    buf[buflen - 1] = '\0';

    OPENSSL_strlcpy(buf, err, buflen);

    return 1;

#endif

}