Author: ian Date: Mon Dec 21 17:17:00 2015 New Revision: 292552 URL: https://svnweb.freebsd.org/changeset/base/292552
Log: Avoid unaligned memory accesses when encoding netbios names in libsmb. The current code for encoding a netbios name converts each byte to a 16-bit value and stores the result by casting a char* to u_short*, resulting in alignment faults on strict-alignment platforms. This change reimplements the encoding routine using only byte accesses to memory. There is no particular reason to work with 16-bit values just because the encoding process creates two bytes of output for every byte of input. Working a byte at at time also avoids endian problems for big-endian platforms. PR: 180438 PR: 189415 Differential Revision: https://reviews.freebsd.org/D4622 Modified: head/contrib/smbfs/lib/smb/nb_name.c Modified: head/contrib/smbfs/lib/smb/nb_name.c ============================================================================== --- head/contrib/smbfs/lib/smb/nb_name.c Mon Dec 21 17:15:03 2015 (r292551) +++ head/contrib/smbfs/lib/smb/nb_name.c Mon Dec 21 17:17:00 2015 (r292552) @@ -143,15 +143,13 @@ nb_encname_len(const char *str) return len; } -#define NBENCODE(c) (htole16((u_short)(((u_char)(c) >> 4) | \ - (((u_char)(c) & 0xf) << 8)) + 0x4141)) - -static void -memsetw(char *dst, int n, u_short word) +static inline void +nb_char_encode(u_char **ptr, u_char c, int n) { + while (n--) { - *(u_short*)dst = word; - dst += 2; + *(*ptr)++ = 0x41 + (c >> 4); + *(*ptr)++ = 0x41 + (c & 0x0f); } } @@ -165,19 +163,15 @@ nb_name_encode(struct nb_name *np, u_cha *cp++ = NB_ENCNAMELEN; name = np->nn_name; if (name[0] == '*' && name[1] == 0) { - *(u_short*)cp = NBENCODE('*'); - memsetw(cp + 2, NB_NAMELEN - 1, NBENCODE(' ')); - cp += NB_ENCNAMELEN; + nb_char_encode(&cp, '*', 1); + nb_char_encode(&cp, ' ', NB_NAMELEN - 1); } else { - for (i = 0; *name && i < NB_NAMELEN - 1; i++, cp += 2, name++) - *(u_short*)cp = NBENCODE(toupper(*name)); - i = NB_NAMELEN - i - 1; - if (i > 0) { - memsetw(cp, i, NBENCODE(' ')); - cp += i * 2; - } - *(u_short*)cp = NBENCODE(np->nn_type); - cp += 2; + for (i = 0; i < NB_NAMELEN - 1; i++) + if (*name != 0) + nb_char_encode(&cp, toupper(*name++), 1); + else + nb_char_encode(&cp, ' ', 1); + nb_char_encode(&cp, np->nn_type, 1); } *cp = 0; if (np->nn_scope == NULL) _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
