svn commit: r292552 - head/contrib/smbfs/lib/smb
Ian Lepore
ian at FreeBSD.org
Mon Dec 21 17:17:01 UTC 2015
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)
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