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- From 553702980ae89c83f2d6e254d62cf82e204956d0 Mon Sep 17 00:00:00 2001
- From: "Christoph M. Becker" <cmbecker69@gmx.de>
- Date: Thu, 17 Jan 2019 11:54:55 +0100
- Subject: [PATCH] Fix #492: Potential double-free in gdImage*Ptr()
- Whenever `gdImage*Ptr()` calls `gdImage*Ctx()` and the latter fails, we
- must not call `gdDPExtractData()`; otherwise a double-free would
- happen. Since `gdImage*Ctx()` are void functions, and we can't change
- that for BC reasons, we're introducing static helpers which are used
- internally.
- We're adding a regression test for `gdImageJpegPtr()`, but not for
- `gdImageGifPtr()` and `gdImageWbmpPtr()` since we don't know how to
- trigger failure of the respective `gdImage*Ctx()` calls.
- This potential security issue has been reported by Solmaz Salimi (aka.
- Rooney).
- CVE-2019-6978
- [Peter: drop tests]
- Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
- ---
- src/gd_gif_out.c | 18 +++++++++++++++---
- src/gd_jpeg.c | 20 ++++++++++++++++----
- src/gd_wbmp.c | 21 ++++++++++++++++++---
- 3 files changed, 84 insertions(+), 11 deletions(-)
- diff --git a/src/gd_gif_out.c b/src/gd_gif_out.c
- index 298a581..d5a9534 100644
- --- a/src/gd_gif_out.c
- +++ b/src/gd_gif_out.c
- @@ -99,6 +99,7 @@ static void char_init(GifCtx *ctx);
- static void char_out(int c, GifCtx *ctx);
- static void flush_char(GifCtx *ctx);
-
- +static int _gdImageGifCtx(gdImagePtr im, gdIOCtxPtr out);
-
-
-
- @@ -131,8 +132,11 @@ BGD_DECLARE(void *) gdImageGifPtr(gdImagePtr im, int *size)
- void *rv;
- gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
- if (out == NULL) return NULL;
- - gdImageGifCtx(im, out);
- - rv = gdDPExtractData(out, size);
- + if (!_gdImageGifCtx(im, out)) {
- + rv = gdDPExtractData(out, size);
- + } else {
- + rv = NULL;
- + }
- out->gd_free(out);
- return rv;
- }
- @@ -220,6 +224,12 @@ BGD_DECLARE(void) gdImageGif(gdImagePtr im, FILE *outFile)
-
- */
- BGD_DECLARE(void) gdImageGifCtx(gdImagePtr im, gdIOCtxPtr out)
- +{
- + _gdImageGifCtx(im, out);
- +}
- +
- +/* returns 0 on success, 1 on failure */
- +static int _gdImageGifCtx(gdImagePtr im, gdIOCtxPtr out)
- {
- gdImagePtr pim = 0, tim = im;
- int interlace, BitsPerPixel;
- @@ -231,7 +241,7 @@ BGD_DECLARE(void) gdImageGifCtx(gdImagePtr im, gdIOCtxPtr out)
- based temporary image. */
- pim = gdImageCreatePaletteFromTrueColor(im, 1, 256);
- if(!pim) {
- - return;
- + return 1;
- }
- tim = pim;
- }
- @@ -247,6 +257,8 @@ BGD_DECLARE(void) gdImageGifCtx(gdImagePtr im, gdIOCtxPtr out)
- /* Destroy palette based temporary image. */
- gdImageDestroy( pim);
- }
- +
- + return 0;
- }
-
-
- diff --git a/src/gd_jpeg.c b/src/gd_jpeg.c
- index fc05842..96ef430 100644
- --- a/src/gd_jpeg.c
- +++ b/src/gd_jpeg.c
- @@ -117,6 +117,8 @@ static void fatal_jpeg_error(j_common_ptr cinfo)
- exit(99);
- }
-
- +static int _gdImageJpegCtx(gdImagePtr im, gdIOCtx *outfile, int quality);
- +
- /*
- * Write IM to OUTFILE as a JFIF-formatted JPEG image, using quality
- * QUALITY. If QUALITY is in the range 0-100, increasing values
- @@ -231,8 +233,11 @@ BGD_DECLARE(void *) gdImageJpegPtr(gdImagePtr im, int *size, int quality)
- void *rv;
- gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
- if (out == NULL) return NULL;
- - gdImageJpegCtx(im, out, quality);
- - rv = gdDPExtractData(out, size);
- + if (!_gdImageJpegCtx(im, out, quality)) {
- + rv = gdDPExtractData(out, size);
- + } else {
- + rv = NULL;
- + }
- out->gd_free(out);
- return rv;
- }
- @@ -253,6 +258,12 @@ void jpeg_gdIOCtx_dest(j_compress_ptr cinfo, gdIOCtx *outfile);
-
- */
- BGD_DECLARE(void) gdImageJpegCtx(gdImagePtr im, gdIOCtx *outfile, int quality)
- +{
- + _gdImageJpegCtx(im, outfile, quality);
- +}
- +
- +/* returns 0 on success, 1 on failure */
- +static int _gdImageJpegCtx(gdImagePtr im, gdIOCtx *outfile, int quality)
- {
- struct jpeg_compress_struct cinfo;
- struct jpeg_error_mgr jerr;
- @@ -287,7 +298,7 @@ BGD_DECLARE(void) gdImageJpegCtx(gdImagePtr im, gdIOCtx *outfile, int quality)
- if(row) {
- gdFree(row);
- }
- - return;
- + return 1;
- }
-
- cinfo.err->emit_message = jpeg_emit_message;
- @@ -328,7 +339,7 @@ BGD_DECLARE(void) gdImageJpegCtx(gdImagePtr im, gdIOCtx *outfile, int quality)
- if(row == 0) {
- gd_error("gd-jpeg: error: unable to allocate JPEG row structure: gdCalloc returns NULL\n");
- jpeg_destroy_compress(&cinfo);
- - return;
- + return 1;
- }
-
- rowptr[0] = row;
- @@ -405,6 +416,7 @@ BGD_DECLARE(void) gdImageJpegCtx(gdImagePtr im, gdIOCtx *outfile, int quality)
- jpeg_finish_compress(&cinfo);
- jpeg_destroy_compress(&cinfo);
- gdFree(row);
- + return 0;
- }
-
-
- diff --git a/src/gd_wbmp.c b/src/gd_wbmp.c
- index f19a1c9..a49bdbe 100644
- --- a/src/gd_wbmp.c
- +++ b/src/gd_wbmp.c
- @@ -88,6 +88,8 @@ int gd_getin(void *in)
- return (gdGetC((gdIOCtx *)in));
- }
-
- +static int _gdImageWBMPCtx(gdImagePtr image, int fg, gdIOCtx *out);
- +
- /*
- Function: gdImageWBMPCtx
-
- @@ -100,6 +102,12 @@ int gd_getin(void *in)
- out - the stream where to write
- */
- BGD_DECLARE(void) gdImageWBMPCtx(gdImagePtr image, int fg, gdIOCtx *out)
- +{
- + _gdImageWBMPCtx(image, fg, out);
- +}
- +
- +/* returns 0 on success, 1 on failure */
- +static int _gdImageWBMPCtx(gdImagePtr image, int fg, gdIOCtx *out)
- {
- int x, y, pos;
- Wbmp *wbmp;
- @@ -107,7 +115,7 @@ BGD_DECLARE(void) gdImageWBMPCtx(gdImagePtr image, int fg, gdIOCtx *out)
- /* create the WBMP */
- if((wbmp = createwbmp(gdImageSX(image), gdImageSY(image), WBMP_WHITE)) == NULL) {
- gd_error("Could not create WBMP\n");
- - return;
- + return 1;
- }
-
- /* fill up the WBMP structure */
- @@ -123,11 +131,15 @@ BGD_DECLARE(void) gdImageWBMPCtx(gdImagePtr image, int fg, gdIOCtx *out)
-
- /* write the WBMP to a gd file descriptor */
- if(writewbmp(wbmp, &gd_putout, out)) {
- + freewbmp(wbmp);
- gd_error("Could not save WBMP\n");
- + return 1;
- }
-
- /* des submitted this bugfix: gdFree the memory. */
- freewbmp(wbmp);
- +
- + return 0;
- }
-
- /*
- @@ -271,8 +283,11 @@ BGD_DECLARE(void *) gdImageWBMPPtr(gdImagePtr im, int *size, int fg)
- void *rv;
- gdIOCtx *out = gdNewDynamicCtx(2048, NULL);
- if (out == NULL) return NULL;
- - gdImageWBMPCtx(im, fg, out);
- - rv = gdDPExtractData(out, size);
- + if (!_gdImageWBMPCtx(im, fg, out)) {
- + rv = gdDPExtractData(out, size);
- + } else {
- + rv = NULL;
- + }
- out->gd_free(out);
- return rv;
- }
- --
- 2.20.1
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