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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
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=292552
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@ -143,15 +143,13 @@ nb_encname_len(const char *str)
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return len;
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}
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#define NBENCODE(c) (htole16((u_short)(((u_char)(c) >> 4) | \
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(((u_char)(c) & 0xf) << 8)) + 0x4141))
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static void
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memsetw(char *dst, int n, u_short word)
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static inline void
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nb_char_encode(u_char **ptr, u_char c, int n)
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{
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while (n--) {
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*(u_short*)dst = word;
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dst += 2;
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*(*ptr)++ = 0x41 + (c >> 4);
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*(*ptr)++ = 0x41 + (c & 0x0f);
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}
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}
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@ -165,19 +163,15 @@ nb_name_encode(struct nb_name *np, u_char *dst)
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*cp++ = NB_ENCNAMELEN;
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name = np->nn_name;
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if (name[0] == '*' && name[1] == 0) {
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*(u_short*)cp = NBENCODE('*');
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memsetw(cp + 2, NB_NAMELEN - 1, NBENCODE(' '));
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cp += NB_ENCNAMELEN;
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nb_char_encode(&cp, '*', 1);
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nb_char_encode(&cp, ' ', NB_NAMELEN - 1);
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} else {
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for (i = 0; *name && i < NB_NAMELEN - 1; i++, cp += 2, name++)
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*(u_short*)cp = NBENCODE(toupper(*name));
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i = NB_NAMELEN - i - 1;
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if (i > 0) {
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memsetw(cp, i, NBENCODE(' '));
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cp += i * 2;
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}
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*(u_short*)cp = NBENCODE(np->nn_type);
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cp += 2;
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for (i = 0; i < NB_NAMELEN - 1; i++)
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if (*name != 0)
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nb_char_encode(&cp, toupper(*name++), 1);
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else
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nb_char_encode(&cp, ' ', 1);
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nb_char_encode(&cp, np->nn_type, 1);
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}
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*cp = 0;
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if (np->nn_scope == NULL)
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