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stdscan: handle $-escaped symbols starting with $

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For a symbol to start with $, it needs to be escaped with a second
dollar sign: $$. This was not handled correctly, instead $$ was seen
as TOKEN_BASE.

Fix this.

Reported-by: E. C. Masloch <pushbx@ulukai.org>
Fixes: https://bugzilla.nasm.us/show_bug.cgi?id=3392922
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin
2025-09-02 17:55:22 -07:00
parent 5201aab90f
commit 9c3d6ff000
1 changed files with 64 additions and 46 deletions
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110
asm/stdscan.c
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@@ -312,68 +312,86 @@ int stdscan(void *private_data, struct tokenval *tv)
return i;
}
/* Skip id chars and return an appropriate string */
static int stdscan_symbol(struct tokenval *tv)
{
char *p = scan.bufptr;
const char *r = p;
size_t len;
p++; /* Leading character already verified */
/* Skip the entire symbol but only copy up to IDLEN_MAX characters */
while (nasm_isidchar(*p))
p++;
scan.bufptr = p;
len = p - r;
if (len >= IDLEN_MAX)
len = IDLEN_MAX - 1;
tv->t_len = len;
tv->t_charptr = stdscan_copy(r, len);
return tv->t_type = TOKEN_ID;
}
static int stdscan_token(struct tokenval *tv)
{
const char *r;
/* we have a token; either an id, a number, operator or char */
if (nasm_isidstart(*scan.bufptr) ||
(*scan.bufptr == '$' && nasm_isidstart(scan.bufptr[1]))) {
/* now we've got an identifier */
bool is_sym = false;
if (nasm_isidstart(*scan.bufptr)) {
int token_type;
if (*scan.bufptr == '$') {
is_sym = true;
scan.bufptr++;
}
r = scan.bufptr++;
/* read the entire buffer to advance the buffer pointer but... */
while (nasm_isidchar(*scan.bufptr))
scan.bufptr++;
/* ... copy only up to IDLEN_MAX-1 characters */
tv->t_charptr = stdscan_copy(r, scan.bufptr - r < IDLEN_MAX ?
scan.bufptr - r : IDLEN_MAX - 1);
if (is_sym || scan.bufptr - r > MAX_KEYWORD)
return tv->t_type = TOKEN_ID; /* bypass all other checks */
token_type = nasm_token_hash(tv->t_charptr, tv);
if (unlikely(tv->t_flag & TFLAG_WARN)) {
/*! ptr [on] non-NASM keyword used in other assemblers
*! warns about keywords used in other assemblers that
*! might indicate a mistake in the source code.
*! Currently only the MASM \c{PTR} keyword is
*! recognized. If (limited) MASM compatibility is
*! desired, the \c{%use masm} macro package is
*! available, see \k{pkg_masm}; however, carefully note
*! the caveats listed.
*/
nasm_warn(WARN_PTR, "`%s' is not a NASM keyword",
tv->t_charptr);
}
if (likely(!(tv->t_flag & TFLAG_BRC))) {
/* most of the tokens fall into this case */
return token_type;
} else {
return tv->t_type = TOKEN_ID;
stdscan_symbol(tv);
if (tv->t_len <= MAX_KEYWORD) {
/* Check to see if it is a keyword of some kind */
token_type = nasm_token_hash(tv->t_charptr, tv);
if (unlikely(tv->t_flag & TFLAG_WARN)) {
/*! ptr [on] non-NASM keyword used in other assemblers
*! warns about keywords used in other assemblers that
*! might indicate a mistake in the source code.
*! Currently only the MASM \c{PTR} keyword is
*! recognized. If (limited) MASM compatibility is
*! desired, the \c{%use masm} macro package is
*! available, see \k{pkg_masm}; however, carefully note
*! the caveats listed.
*/
nasm_warn(WARN_PTR, "`%s' is not a NASM keyword",
tv->t_charptr);
}
if (likely(!(tv->t_flag & TFLAG_BRC))) {
/* most of the tokens fall into this case */
return token_type;
}
}
return tv->t_type = TOKEN_ID;
} else if (*scan.bufptr == '$' && !nasm_isnumchar(scan.bufptr[1])) {
/*
* It's a $ sign with no following hex number; this must
* mean it's a Here token ($), evaluating to the current
* assembly location, or a Base token ($$), evaluating to
* the base of the current segment.
* assembly location, a Base token ($$), evaluating to
* the base of the current segment, or an identifier beginning
* with $ (escaped by a previous $).
*/
scan.bufptr++;
if (*scan.bufptr == '$') {
scan.bufptr++;
return tv->t_type = TOKEN_BASE;
if (nasm_isidchar(scan.bufptr[1])) {
/* $-escaped symbol starting with $ */
return stdscan_symbol(tv);
} else {
scan.bufptr++;
return tv->t_type = TOKEN_BASE;
}
} else if (nasm_isidstart(*scan.bufptr)) {
/* $-escaped symbol that does NOT start with $ */
return stdscan_symbol(tv);
} else {
return tv->t_type = TOKEN_HERE;
}
return tv->t_type = TOKEN_HERE;
} else if (nasm_isnumstart(*scan.bufptr)) { /* now we've got a number */
bool rn_error;
bool is_hex = false;