Port fix for libgd bug 447 (GH-17320)

That bug has been potentially exploitable[1], but the GD extension was
not affected by that, because `gdImageBmpPtr()` is never called.  Still
it seems to be reasonable to port the fix; if only to keep bundled and
external libgd synced.

[1] <https://github.com/advisories/GHSA-hc3p-jvff-jfw5>
This commit is contained in:
Christoph M. Becker 2025-01-03 12:57:12 +01:00 committed by GitHub
parent 2dfe92767d
commit 11d701a6ab
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GPG key ID: B5690EEEBB952194

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@ -40,6 +40,8 @@ static int bmp_read_4bit(gdImagePtr im, gdIOCtxPtr infile, bmp_info_t *info, bmp
static int bmp_read_8bit(gdImagePtr im, gdIOCtxPtr infile, bmp_info_t *info, bmp_hdr_t *header);
static int bmp_read_rle(gdImagePtr im, gdIOCtxPtr infile, bmp_info_t *info);
static int _gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression);
#define BMP_DEBUG(s)
static int gdBMPPutWord(gdIOCtx *out, int w)
@ -68,8 +70,10 @@ void * gdImageBmpPtr(gdImagePtr im, int *size, int compression)
void *rv;
gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
if (out == NULL) return NULL;
gdImageBmpCtx(im, out, compression);
if (!_gdImageBmpCtx(im, out, compression))
rv = gdDPExtractData(out, size);
else
rv = NULL;
out->gd_free(out);
return rv;
}
@ -90,12 +94,17 @@ void gdImageBmp(gdImagePtr im, FILE *outFile, int compression)
*/
void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
{
_gdImageBmpCtx(im, out, compression);
}
static int _gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression){
int bitmap_size = 0, info_size, total_size, padding;
int i, row, xpos, pixel;
int error = 0;
unsigned char *uncompressed_row = NULL, *uncompressed_row_start = NULL;
FILE *tmpfile_for_compression = NULL;
gdIOCtxPtr out_original = NULL;
int ret = 1;
/* No compression if its true colour or we don't support seek */
if (im->trueColor) {
@ -273,6 +282,7 @@ void gdImageBmpCtx(gdImagePtr im, gdIOCtxPtr out, int compression)
out_original = NULL;
}
ret = 0;
cleanup:
if (tmpfile_for_compression) {
#ifdef _WIN32
@ -286,7 +296,7 @@ cleanup:
if (out_original) {
out_original->gd_free(out_original);
}
return;
return ret;
}
static int compress_row(unsigned char *row, int length)