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Teach the GIF library about read errors.
--- a/liblcdf/gifread.c
+++ b/liblcdf/gifread.c
@@ -57,7 +57,7 @@
int is_record;
int is_eoi;
uint8_t (*byte_getter)(struct Gif_Reader *);
- void (*block_getter)(uint8_t *, uint32_t, struct Gif_Reader *);
+ int (*block_getter)(uint8_t *, uint32_t, struct Gif_Reader *);
uint32_t (*offseter)(struct Gif_Reader *);
int (*eofer)(struct Gif_Reader *);
@@ -86,10 +86,10 @@
return i == EOF ? 0 : (uint8_t)i;
}
-static void
+int
file_block_getter(uint8_t *p, uint32_t s, Gif_Reader *grr)
{
- fread(p, 1, s, grr->f);
+ return fread(p, 1, s, grr->f) == s;
}
static uint32_t
@@ -117,12 +117,16 @@
return grr->w ? (grr->w--, *grr->v++) : 0;
}
-static void
+static int
record_block_getter(uint8_t *p, uint32_t s, Gif_Reader *grr)
{
- if (s > grr->w) s = grr->w;
+ int res;
+ res = (s <= grr->w);
+ if (!res)
+ s = grr->w;
memcpy(p, grr->v, s);
grr->w -= s, grr->v += s;
+ return res;
}
static uint32_t
@@ -215,7 +219,8 @@
block_len = gifgetbyte(grr);
GIF_DEBUG(("\nimage_block(%d)", block_len));
if (block_len == 0) return 0;
- gifgetblock(buffer + bit_length / 8, block_len, grr);
+ if (!gifgetblock(buffer + bit_length / 8, block_len, grr))
+ return 0;
bit_length += block_len * 8;
}
@@ -362,7 +367,8 @@
i = gifgetbyte(grr);
GIF_DEBUG(("\nafter_image(%d)\n", i));
while (i > 0) {
- gifgetblock(buffer, i, grr);
+ if (!gifgetblock(buffer, i, grr))
+ break;
i = gifgetbyte(grr);
GIF_DEBUG(("\nafter_image(%d)\n", i));
}
@@ -477,7 +483,8 @@
if (!comp) return 0;
}
comp[comp_len] = i;
- gifgetblock(comp + comp_len + 1, i, grr);
+ if (!gifgetblock(comp + comp_len + 1, i, grr))
+ break;
comp_len += i + 1;
i = gifgetbyte(grr);
}
@@ -584,7 +591,8 @@
uint8_t buffer[GIF_MAX_BLOCK];
int i = gifgetbyte(grr);
while (i > 0) {
- gifgetblock(buffer, i, grr);
+ if (!gifgetblock(buffer, i, grr))
+ break;
i = gifgetbyte(grr);
}
}
@@ -614,13 +622,15 @@
if (len > 0) {
gif_read_error(gfc, "odd graphic extension format");
- gifgetblock(crap, len, grr);
+ if (!gifgetblock(crap, len, grr))
+ return;
}
len = gifgetbyte(grr);
while (len > 0) {
gif_read_error(gfc, "odd graphic extension format");
- gifgetblock(crap, len, grr);
+ if (!gifgetblock(crap, len, grr))
+ break;
len = gifgetbyte(grr);
}
}
@@ -638,7 +648,8 @@
while (len > 0) {
Gif_ReArray(data, char, total_len + len + 1);
if (!data) return 0;
- gifgetblock((uint8_t *)data, len, grr);
+ if (!gifgetblock((uint8_t *)data, len, grr))
+ break;
total_len += len;
data[total_len] = 0;
@@ -664,7 +675,8 @@
if (data) Gif_ReArray(data, uint8_t, data_len + block_len + 1);
else data = Gif_NewArray(uint8_t, block_len + 1);
if (!data) goto done;
- gifgetblock(data + data_len, block_len, grr);
+ if (!gifgetblock(data + data_len, block_len, grr))
+ break;
data_len += block_len;
block_len = gifgetbyte(grr);
}
@@ -682,7 +694,8 @@
if (!gfex) Gif_DeleteArray(data);
while (block_len > 0) {
uint8_t buffer[GIF_MAX_BLOCK];
- gifgetblock(buffer, block_len, grr);
+ if (!gifgetblock(buffer, block_len, grr))
+ break;
block_len = gifgetbyte(grr);
}
return gfex != 0;
@@ -695,7 +708,10 @@
Gif_Stream *gfs = gfc->stream;
uint8_t buffer[GIF_MAX_BLOCK + 1];
uint8_t len = gifgetbyte(grr);
- gifgetblock(buffer, len, grr);
+ if (!gifgetblock(buffer, len, grr)) {
+ gif_read_error(gfc, "bad application extension");
+ return 0;
+ }
/* Read the Netscape loop extension. */
if (len == 11 && memcmp(buffer, "NETSCAPE2.0", 11) == 0) {
@@ -710,7 +726,8 @@
gif_read_error(gfc, "bad loop extension");
while (len > 0) {
- gifgetblock(buffer, len, grr);
+ if (!gifgetblock(buffer, len, grr))
+ break;
len = gifgetbyte(grr);
}
return 1;
|
