Skip to content

Fix integer overflow in quantize_pngquant() #9474

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
myagmartseren wants to merge 3 commits into
base: main
Choose a base branch
from
+12 −4
Open

Fix integer overflow in quantize_pngquant() #9474

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
9ff51ff
Fix integer overflow in quantize_pngquant() and replace sprintf
Mar 19, 2026
a6f8610
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Mar 19, 2026
3a2e005
Removed unrelated snprintf change
radarhere Mar 29, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 12 additions & 4 deletions src/libImaging/QuantPngQuant.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
*
*/

#include <stdint.h>
Copy link
Copy Markdown
Member

@radarhere radarhere Apr 11, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change
#include <stdint.h>

This should already be included by

Pillow/src/libImaging/QuantTypes.h

Lines 15 to 20 in b04c9a3

#ifdef _MSC_VER
typedef unsigned __int32 uint32_t;
typedef unsigned __int64 uint64_t;
#else
#include <stdint.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
Expand Down Expand Up @@ -39,6 +40,13 @@ quantize_pngquant(
*paletteLength = 0;
*quantizedPixels = NULL;

/* Check for integer overflow in width * height to prevent
* undersized allocations leading to heap buffer overflow. */
if (height != 0 && (size_t)width > SIZE_MAX / (size_t)height) {
goto err;
}
size_t total_pixels = (size_t)width * (size_t)height;

/* configure pngquant */
attr = liq_attr_create();
if (!attr) {
Expand Down Expand Up @@ -77,7 +85,7 @@ quantize_pngquant(
}

/* write output pixels (pngquant uses char array) */
charMatrix = malloc(width * height);
charMatrix = malloc(total_pixels);
if (!charMatrix) {
goto err;
}
Expand All @@ -86,18 +94,18 @@ quantize_pngquant(
goto err;
}
for (y = 0; y < height; y++) {
charMatrixRows[y] = &charMatrix[y * width];
charMatrixRows[y] = &charMatrix[(size_t)y * width];
}
if (LIQ_OK != liq_write_remapped_image_rows(remap, image, charMatrixRows)) {
goto err;
}

/* transcribe output pixels (pillow uses uint32_t array) */
*quantizedPixels = malloc(sizeof(uint32_t) * width * height);
*quantizedPixels = malloc(sizeof(uint32_t) * total_pixels);
if (!*quantizedPixels) {
goto err;
}
for (i = 0; i < width * height; i++) {
for (i = 0; i < total_pixels; i++) {
(*quantizedPixels)[i] = charMatrix[i];
}

Expand Down
Loading