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authorH. Peter Anvin (Intel) <hpa@zytor.com>2019-09-18 21:20:52 -0700
committerH. Peter Anvin (Intel) <hpa@zytor.com>2019-09-18 21:20:52 -0700
commitf7dbdb2e136db99051b14403a0f29c5155bbf7d8 (patch)
treefe82b12e9e4c94f1dfa67d167c33e6c41ce4cadd /asm/preproc.c
parentf24d97500847ed02b62f04dc5d93e1b237c282de (diff)
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preproc: fix multiple memory corruption issues
paste_tokens() would not null-terminate the buffer before passing it to tokenize(), resulting in garbage or a memory overwrite. In several places the next pointers got confused; sometimes causing a circular list and sometimes an invalid pointer. Some minor code cleanups while fixing things, too... Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Diffstat (limited to 'asm/preproc.c')
-rw-r--r--asm/preproc.c192
1 files changed, 104 insertions, 88 deletions
diff --git a/asm/preproc.c b/asm/preproc.c
index c94f9b68..f63594df 100644
--- a/asm/preproc.c
+++ b/asm/preproc.c
@@ -264,8 +264,7 @@ static bool is_smac_param(enum pp_token_type toktype)
return toktype >= TOK_SMAC_START_PARAMS;
}
-#define PP_CONCAT_MASK(x) (1 << (x))
-#define PP_CONCAT_MATCH(t, mask) (PP_CONCAT_MASK((t)->type) & mask)
+#define PP_CONCAT_MASK(x) (1U << (x))
struct tokseq_match {
int mask_head;
@@ -746,7 +745,8 @@ static Token *dup_tlistn(const Token *list, size_t cnt, Token ***tailp)
if (tailp) {
**tailp = newlist;
- *tailp = tailpp;
+ if (newlist)
+ *tailp = tailpp;
}
return newlist;
@@ -1977,7 +1977,7 @@ static int read_param_count(const char *str)
*/
static void count_mmac_params(Token * t, int *nparamp, Token ***paramsp)
{
- int paramsize, brace;
+ int paramsize;
int nparam = 0;
Token **params;
@@ -1991,16 +1991,12 @@ static void count_mmac_params(Token * t, int *nparamp, Token ***paramsp)
paramsize += PARAM_DELTA;
params = nasm_realloc(params, sizeof(*params) * paramsize);
}
- brace = 0;
- if (tok_is(t, '{'))
- brace++;
params[++nparam] = t;
- if (brace) {
+ if (tok_is(t, '{')) {
+ int brace = 1;
while (brace && (t = t->next)) {
- if (tok_is(t, '{'))
- brace++;
- else if (tok_is(t, '}'))
- brace--;
+ brace += tok_is(t, '{');
+ brace -= tok_is(t, '}');
}
if (t) {
@@ -2009,8 +2005,10 @@ static void count_mmac_params(Token * t, int *nparamp, Token ***paramsp)
* for the comma.
*/
t = skip_white(t->next);
- if (!tok_is(t, ','))
+ if (tok_isnt(t, ','))
nasm_nonfatal("braces do not enclose all of macro parameter");
+ } else {
+ nasm_nonfatal("expecting closing brace in macro parameter");
}
}
@@ -4112,6 +4110,11 @@ static int find_cc(Token * t)
return bsii(t->text, (const char **)conditions, ARRAY_SIZE(conditions));
}
+static inline bool pp_concat_match(const Token *t, unsigned int mask)
+{
+ return t && (PP_CONCAT_MASK(t->type) & mask);
+}
+
/*
* This routines walks over tokens strem and handles tokens
* pasting, if @handle_explicit passed then explicit pasting
@@ -4140,19 +4143,18 @@ static bool paste_tokens(Token **head, const struct tokseq_match *m,
* A -> BC -> D
*/
tok = *head;
- prev_next = NULL;
+ prev_next = prev_nonspace = head;
- if (!tok_white(tok) && !tok_type(tok, TOK_PASTE))
- prev_nonspace = head;
- else
+ if (tok_white(tok) || tok_type(tok, TOK_PASTE))
prev_nonspace = NULL;
while (tok && (next = tok->next)) {
+ bool did_paste = false;
switch (tok->type) {
case TOK_WHITESPACE:
/* Zap redundant whitespaces */
- next = zap_white(next);
+ tok->next = next = zap_white(next);
break;
case TOK_PASTE:
@@ -4167,7 +4169,9 @@ static bool paste_tokens(Token **head, const struct tokseq_match *m,
break;
}
- pasted = true;
+ did_paste = true;
+
+ prev_next = prev_nonspace;
t = *prev_nonspace;
/* Delete leading whitespace */
@@ -4194,7 +4198,7 @@ static bool paste_tokens(Token **head, const struct tokseq_match *m,
* whitespace after paste token.
*/
if (!next) {
- tok = NULL; /* End of line */
+ *prev_nonspace = tok = NULL; /* End of line */
break;
}
@@ -4214,77 +4218,67 @@ static bool paste_tokens(Token **head, const struct tokseq_match *m,
t = new_White(NULL);
}
- /* We want to restart from the head of the pasted token */
*prev_nonspace = tok = t;
while (t->next)
t = t->next; /* Find the last token produced */
/* Delete the second token and attach to the end of the list */
t->next = delete_Token(next);
+
+ /* We want to restart from the head of the pasted token */
+ next = tok;
break;
default:
/* implicit pasting */
for (i = 0; i < mnum; i++) {
- if (!(PP_CONCAT_MATCH(tok, m[i].mask_head)))
- continue;
+ if (pp_concat_match(tok, m[i].mask_head))
+ break;
+ }
- len = 0;
- while (next && PP_CONCAT_MATCH(next, m[i].mask_tail)) {
- len += next->len;
- next = next->next;
- }
+ if (i >= mnum)
+ break;
- /* No match or no text to process */
- if (tok == next || len == 0)
- break;
+ len = tok->len;
+ while (pp_concat_match(next, m[i].mask_tail)) {
+ len += next->len;
+ next = next->next;
+ }
- len += tok->len;
- p = buf = nasm_malloc(len + 1);
+ /* No match or no text to process */
+ if (len == tok->len)
+ break;
+ p = buf = nasm_malloc(len + 1);
+ while (tok != next) {
p = mempcpy(p, tok->text, tok->len);
tok = delete_Token(tok);
-
- while (tok != next) {
- if (PP_CONCAT_MATCH(tok, m[i].mask_tail)) {
- p = mempcpy(p, tok->text, tok->len);
- tok = delete_Token(tok);
- }
- tok = delete_Token(tok);
- }
-
- tok = tokenize(buf);
- nasm_free(buf);
-
- if (prev_next)
- *prev_next = tok;
- else
- *head = tok;
-
- /*
- * Connect pasted into original stream,
- * ie A -> new-tokens -> B
- */
- while (tok && tok->next)
- tok = tok->next;
- tok->next = next;
-
- pasted = true;
-
- /* Restart from pasted tokens head */
- tok = prev_next ? *prev_next : *head;
}
+ *p = '\0';
+ *prev_next = tok = t = tokenize(buf);
+ nasm_free(buf);
+ /*
+ * Connect pasted into original stream,
+ * ie A -> new-tokens -> B
+ */
+ while (t->next)
+ t = t->next;
+ t->next = next;
+ prev_next = prev_nonspace = &t->next;
+ did_paste = true;
break;
}
- prev_next = &tok->next;
-
- if (tok->next && !tok_white(tok->next) &&
- !tok_type(tok->next, TOK_PASTE))
- prev_nonspace = prev_next;
+ if (did_paste) {
+ pasted = true;
+ } else {
+ prev_next = &tok->next;
+ if (next && next->type != TOK_WHITESPACE && next->type != TOK_PASTE)
+ prev_nonspace = prev_next;
+ }
- tok = tok->next;
+ tok = next;
}
return pasted;
@@ -4947,7 +4941,7 @@ static SMacro *expand_one_smacro(Token ***tpp)
t = m->expand(m, params, nparam);
tafter = tline->next; /* Skip past the macro call */
- tline->next = NULL; /* Truncate list at the macro call end */
+ tline->next = NULL; /* Truncate list at the macro call end */
tline = tafter;
tup = NULL;
@@ -5492,33 +5486,55 @@ static int expand_mmacro(Token * tline)
nasm_assert(params[nparam+1] == NULL);
for (i = 1; (t = params[i]); i++) {
+ bool braced = false;
int brace = 0;
+ int white = 0;
bool comma = !m->plus || i < nparam;
t = skip_white(t);
- if (tok_is(t, '{'))
- t = t->next, brace++, comma = false;
+ if (tok_is(t, '{')) {
+ t = t->next;
+ brace = 1;
+ braced = true;
+ comma = false;
+ }
+
params[i] = t;
- while (t) {
- if (comma) {
- /* Check if we hit a comma that ends this argument */
- Token *tns = skip_white(t);
- if (tok_is(tns, ','))
- break;
+ for (; t; t = t->next) {
+ if (tok_white(t)) {
+ white++;
+ continue;
}
- if (brace && t->type == TOK_OTHER && t->len == 1) {
- const char c = t->text[0];
- if (c == '{')
- brace++; /* ... or a nested opening brace */
- else if (c == '}')
- if (!--brace)
- break; /* ... or a brace */
+
+ if (t->type == TOK_OTHER && t->len == 1) {
+ switch (t->text[0]) {
+ case ',':
+ if (comma && !brace)
+ goto endparam;
+ break;
+
+ case '{':
+ brace++;
+ break;
+
+ case '}':
+ brace--;
+ if (braced && !brace) {
+ paramlen[i] += white;
+ goto endparam;
+ }
+ break;
+
+ default:
+ break;
+ }
}
- t = t->next;
- paramlen[i]++;
+
+ paramlen[i] += white + 1;
+ white = 0;
}
- if (brace)
- nasm_nonfatal("macro params should be enclosed in braces");
+ endparam:
+ ;
}
/*