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git/quote.c
Jeff King 8424981934 Fix invalid read in quote_c_style_counted
This function did not work on strings that were not NUL-terminated. It
reads through a length-bounded string, searching for characters in need of
quoting. After we find one, we output the quoted character, then advance
our pointer to find the next one. However, we never decremented the
length, meaning we ended up looking at whatever random junk was stored
after the string.

This bug was not found by the existing tests because most code paths feed
a NUL-terminated string. The notable exception is a directory name being
fed by ls-tree.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-02-06 10:55:03 -08:00

480 lines
10 KiB
C

#include "cache.h"
#include "quote.h"
int quote_path_fully = 1;
/* Help to copy the thing properly quoted for the shell safety.
* any single quote is replaced with '\'', any exclamation point
* is replaced with '\!', and the whole thing is enclosed in a
*
* E.g.
* original sq_quote result
* name ==> name ==> 'name'
* a b ==> a b ==> 'a b'
* a'b ==> a'\''b ==> 'a'\''b'
* a!b ==> a'\!'b ==> 'a'\!'b'
*/
static inline int need_bs_quote(char c)
{
return (c == '\'' || c == '!');
}
void sq_quote_buf(struct strbuf *dst, const char *src)
{
char *to_free = NULL;
if (dst->buf == src)
to_free = strbuf_detach(dst, NULL);
strbuf_addch(dst, '\'');
while (*src) {
size_t len = strcspn(src, "'!");
strbuf_add(dst, src, len);
src += len;
while (need_bs_quote(*src)) {
strbuf_addstr(dst, "'\\");
strbuf_addch(dst, *src++);
strbuf_addch(dst, '\'');
}
}
strbuf_addch(dst, '\'');
free(to_free);
}
void sq_quote_print(FILE *stream, const char *src)
{
char c;
fputc('\'', stream);
while ((c = *src++)) {
if (need_bs_quote(c)) {
fputs("'\\", stream);
fputc(c, stream);
fputc('\'', stream);
} else {
fputc(c, stream);
}
}
fputc('\'', stream);
}
void sq_quote_argv(struct strbuf *dst, const char** argv, size_t maxlen)
{
int i;
/* Copy into destination buffer. */
strbuf_grow(dst, 255);
for (i = 0; argv[i]; ++i) {
strbuf_addch(dst, ' ');
sq_quote_buf(dst, argv[i]);
if (maxlen && dst->len > maxlen)
die("Too many or long arguments");
}
}
static char *sq_dequote_step(char *arg, char **next)
{
char *dst = arg;
char *src = arg;
char c;
if (*src != '\'')
return NULL;
for (;;) {
c = *++src;
if (!c)
return NULL;
if (c != '\'') {
*dst++ = c;
continue;
}
/* We stepped out of sq */
switch (*++src) {
case '\0':
*dst = 0;
if (next)
*next = NULL;
return arg;
case '\\':
c = *++src;
if (need_bs_quote(c) && *++src == '\'') {
*dst++ = c;
continue;
}
/* Fallthrough */
default:
if (!next || !isspace(*src))
return NULL;
do {
c = *++src;
} while (isspace(c));
*dst = 0;
*next = src;
return arg;
}
}
}
char *sq_dequote(char *arg)
{
return sq_dequote_step(arg, NULL);
}
int sq_dequote_to_argv(char *arg, const char ***argv, int *nr, int *alloc)
{
char *next = arg;
if (!*arg)
return 0;
do {
char *dequoted = sq_dequote_step(next, &next);
if (!dequoted)
return -1;
ALLOC_GROW(*argv, *nr + 1, *alloc);
(*argv)[(*nr)++] = dequoted;
} while (next);
return 0;
}
/* 1 means: quote as octal
* 0 means: quote as octal if (quote_path_fully)
* -1 means: never quote
* c: quote as "\\c"
*/
#define X8(x) x, x, x, x, x, x, x, x
#define X16(x) X8(x), X8(x)
static signed char const sq_lookup[256] = {
/* 0 1 2 3 4 5 6 7 */
/* 0x00 */ 1, 1, 1, 1, 1, 1, 1, 'a',
/* 0x08 */ 'b', 't', 'n', 'v', 'f', 'r', 1, 1,
/* 0x10 */ X16(1),
/* 0x20 */ -1, -1, '"', -1, -1, -1, -1, -1,
/* 0x28 */ X16(-1), X16(-1), X16(-1),
/* 0x58 */ -1, -1, -1, -1,'\\', -1, -1, -1,
/* 0x60 */ X16(-1), X8(-1),
/* 0x78 */ -1, -1, -1, -1, -1, -1, -1, 1,
/* 0x80 */ /* set to 0 */
};
static inline int sq_must_quote(char c)
{
return sq_lookup[(unsigned char)c] + quote_path_fully > 0;
}
/* returns the longest prefix not needing a quote up to maxlen if positive.
This stops at the first \0 because it's marked as a character needing an
escape */
static size_t next_quote_pos(const char *s, ssize_t maxlen)
{
size_t len;
if (maxlen < 0) {
for (len = 0; !sq_must_quote(s[len]); len++);
} else {
for (len = 0; len < maxlen && !sq_must_quote(s[len]); len++);
}
return len;
}
/*
* C-style name quoting.
*
* (1) if sb and fp are both NULL, inspect the input name and counts the
* number of bytes that are needed to hold c_style quoted version of name,
* counting the double quotes around it but not terminating NUL, and
* returns it.
* However, if name does not need c_style quoting, it returns 0.
*
* (2) if sb or fp are not NULL, it emits the c_style quoted version
* of name, enclosed with double quotes if asked and needed only.
* Return value is the same as in (1).
*/
static size_t quote_c_style_counted(const char *name, ssize_t maxlen,
struct strbuf *sb, FILE *fp, int no_dq)
{
#undef EMIT
#define EMIT(c) \
do { \
if (sb) strbuf_addch(sb, (c)); \
if (fp) fputc((c), fp); \
count++; \
} while (0)
#define EMITBUF(s, l) \
do { \
if (sb) strbuf_add(sb, (s), (l)); \
if (fp) fwrite((s), (l), 1, fp); \
count += (l); \
} while (0)
size_t len, count = 0;
const char *p = name;
for (;;) {
int ch;
len = next_quote_pos(p, maxlen);
if (len == maxlen || (maxlen < 0 && !p[len]))
break;
if (!no_dq && p == name)
EMIT('"');
EMITBUF(p, len);
EMIT('\\');
p += len;
ch = (unsigned char)*p++;
if (maxlen >= 0)
maxlen -= len + 1;
if (sq_lookup[ch] >= ' ') {
EMIT(sq_lookup[ch]);
} else {
EMIT(((ch >> 6) & 03) + '0');
EMIT(((ch >> 3) & 07) + '0');
EMIT(((ch >> 0) & 07) + '0');
}
}
EMITBUF(p, len);
if (p == name) /* no ending quote needed */
return 0;
if (!no_dq)
EMIT('"');
return count;
}
size_t quote_c_style(const char *name, struct strbuf *sb, FILE *fp, int nodq)
{
return quote_c_style_counted(name, -1, sb, fp, nodq);
}
void quote_two_c_style(struct strbuf *sb, const char *prefix, const char *path, int nodq)
{
if (quote_c_style(prefix, NULL, NULL, 0) ||
quote_c_style(path, NULL, NULL, 0)) {
if (!nodq)
strbuf_addch(sb, '"');
quote_c_style(prefix, sb, NULL, 1);
quote_c_style(path, sb, NULL, 1);
if (!nodq)
strbuf_addch(sb, '"');
} else {
strbuf_addstr(sb, prefix);
strbuf_addstr(sb, path);
}
}
void write_name_quoted(const char *name, FILE *fp, int terminator)
{
if (terminator) {
quote_c_style(name, NULL, fp, 0);
} else {
fputs(name, fp);
}
fputc(terminator, fp);
}
void write_name_quotedpfx(const char *pfx, size_t pfxlen,
const char *name, FILE *fp, int terminator)
{
int needquote = 0;
if (terminator) {
needquote = next_quote_pos(pfx, pfxlen) < pfxlen
|| name[next_quote_pos(name, -1)];
}
if (needquote) {
fputc('"', fp);
quote_c_style_counted(pfx, pfxlen, NULL, fp, 1);
quote_c_style(name, NULL, fp, 1);
fputc('"', fp);
} else {
fwrite(pfx, pfxlen, 1, fp);
fputs(name, fp);
}
fputc(terminator, fp);
}
/* quote path as relative to the given prefix */
char *quote_path_relative(const char *in, int len,
struct strbuf *out, const char *prefix)
{
int needquote;
if (len < 0)
len = strlen(in);
/* "../" prefix itself does not need quoting, but "in" might. */
needquote = next_quote_pos(in, len) < len;
strbuf_setlen(out, 0);
strbuf_grow(out, len);
if (needquote)
strbuf_addch(out, '"');
if (prefix) {
int off = 0;
while (prefix[off] && off < len && prefix[off] == in[off])
if (prefix[off] == '/') {
prefix += off + 1;
in += off + 1;
len -= off + 1;
off = 0;
} else
off++;
for (; *prefix; prefix++)
if (*prefix == '/')
strbuf_addstr(out, "../");
}
quote_c_style_counted (in, len, out, NULL, 1);
if (needquote)
strbuf_addch(out, '"');
if (!out->len)
strbuf_addstr(out, "./");
return out->buf;
}
/*
* C-style name unquoting.
*
* Quoted should point at the opening double quote.
* + Returns 0 if it was able to unquote the string properly, and appends the
* result in the strbuf `sb'.
* + Returns -1 in case of error, and doesn't touch the strbuf. Though note
* that this function will allocate memory in the strbuf, so calling
* strbuf_release is mandatory whichever result unquote_c_style returns.
*
* Updates endp pointer to point at one past the ending double quote if given.
*/
int unquote_c_style(struct strbuf *sb, const char *quoted, const char **endp)
{
size_t oldlen = sb->len, len;
int ch, ac;
if (*quoted++ != '"')
return -1;
for (;;) {
len = strcspn(quoted, "\"\\");
strbuf_add(sb, quoted, len);
quoted += len;
switch (*quoted++) {
case '"':
if (endp)
*endp = quoted;
return 0;
case '\\':
break;
default:
goto error;
}
switch ((ch = *quoted++)) {
case 'a': ch = '\a'; break;
case 'b': ch = '\b'; break;
case 'f': ch = '\f'; break;
case 'n': ch = '\n'; break;
case 'r': ch = '\r'; break;
case 't': ch = '\t'; break;
case 'v': ch = '\v'; break;
case '\\': case '"':
break; /* verbatim */
/* octal values with first digit over 4 overflow */
case '0': case '1': case '2': case '3':
ac = ((ch - '0') << 6);
if ((ch = *quoted++) < '0' || '7' < ch)
goto error;
ac |= ((ch - '0') << 3);
if ((ch = *quoted++) < '0' || '7' < ch)
goto error;
ac |= (ch - '0');
ch = ac;
break;
default:
goto error;
}
strbuf_addch(sb, ch);
}
error:
strbuf_setlen(sb, oldlen);
return -1;
}
/* quoting as a string literal for other languages */
void perl_quote_print(FILE *stream, const char *src)
{
const char sq = '\'';
const char bq = '\\';
char c;
fputc(sq, stream);
while ((c = *src++)) {
if (c == sq || c == bq)
fputc(bq, stream);
fputc(c, stream);
}
fputc(sq, stream);
}
void python_quote_print(FILE *stream, const char *src)
{
const char sq = '\'';
const char bq = '\\';
const char nl = '\n';
char c;
fputc(sq, stream);
while ((c = *src++)) {
if (c == nl) {
fputc(bq, stream);
fputc('n', stream);
continue;
}
if (c == sq || c == bq)
fputc(bq, stream);
fputc(c, stream);
}
fputc(sq, stream);
}
void tcl_quote_print(FILE *stream, const char *src)
{
char c;
fputc('"', stream);
while ((c = *src++)) {
switch (c) {
case '[': case ']':
case '{': case '}':
case '$': case '\\': case '"':
fputc('\\', stream);
default:
fputc(c, stream);
break;
case '\f':
fputs("\\f", stream);
break;
case '\r':
fputs("\\r", stream);
break;
case '\n':
fputs("\\n", stream);
break;
case '\t':
fputs("\\t", stream);
break;
case '\v':
fputs("\\v", stream);
break;
}
}
fputc('"', stream);
}