From 169ca8debfdab0b63e5a814315d4e29cfd7bdf16 Mon Sep 17 00:00:00 2001 From: Peter Marko Date: Thu, 27 Nov 2025 19:03:47 +0100 Subject: [PATCH] libpng: patch CVE-2025-64720 Pick commit per NVD report. (From OE-Core rev: 9694df176a13eeac174c7da2bcf8243969dbcda6) Signed-off-by: Peter Marko Signed-off-by: Steve Sakoman --- .../libpng/files/CVE-2025-64720.patch | 103 ++++++++++++++++++ .../libpng/libpng_1.6.39.bb | 1 + 2 files changed, 104 insertions(+) create mode 100644 meta/recipes-multimedia/libpng/files/CVE-2025-64720.patch diff --git a/meta/recipes-multimedia/libpng/files/CVE-2025-64720.patch b/meta/recipes-multimedia/libpng/files/CVE-2025-64720.patch new file mode 100644 index 0000000000..08df7c3210 --- /dev/null +++ b/meta/recipes-multimedia/libpng/files/CVE-2025-64720.patch @@ -0,0 +1,103 @@ +From 08da33b4c88cfcd36e5a706558a8d7e0e4773643 Mon Sep 17 00:00:00 2001 +From: Cosmin Truta +Date: Wed, 12 Nov 2025 13:46:23 +0200 +Subject: [PATCH] Fix a buffer overflow in `png_init_read_transformations` + +The palette compositing code in `png_init_read_transformations` was +incorrectly applying background compositing when PNG_FLAG_OPTIMIZE_ALPHA +was set. This violated the premultiplied alpha invariant +`component <= alpha` expected by `png_image_read_composite`, causing +values that exceeded the valid range for the PNG_sRGB_FROM_LINEAR lookup +tables. + +When PNG_ALPHA_OPTIMIZED is active, palette entries should contain pure +premultiplied RGB values without background compositing. The background +compositing must happen later in `png_image_read_composite` where the +actual background color from the PNG file is available. + +The fix consists in introducing conditional behavior based on +PNG_FLAG_OPTIMIZE_ALPHA: when set, the code performs only +premultiplication using the formula `component * alpha + 127) / 255` +with proper gamma correction. When not set, the original background +compositing calculation based on the `png_composite` macro is preserved. + +This prevents buffer overflows in `png_image_read_composite` where +out-of-range premultiplied values would cause out-of-bounds array access +in `png_sRGB_base[]` and `png_sRGB_delta[]`. + +Reported-by: Samsung-PENTEST +Analyzed-by: John Bowler + +CVE: CVE-2025-64720 +Upstream-Status: Backport [https://github.com/pnggroup/libpng/commit/08da33b4c88cfcd36e5a706558a8d7e0e4773643] +Signed-off-by: Peter Marko +--- + pngrtran.c | 52 ++++++++++++++++++++++++++++++++++++++++++---------- + 1 file changed, 42 insertions(+), 10 deletions(-) + +diff --git a/pngrtran.c b/pngrtran.c +index 548780030..2f5202255 100644 +--- a/pngrtran.c ++++ b/pngrtran.c +@@ -1698,19 +1698,51 @@ png_init_read_transformations(png_structrp png_ptr) + } + else /* if (png_ptr->trans_alpha[i] != 0xff) */ + { +- png_byte v, w; ++ if ((png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0) ++ { ++ /* Premultiply only: ++ * component = round((component * alpha) / 255) ++ */ ++ png_uint_32 component; + +- v = png_ptr->gamma_to_1[palette[i].red]; +- png_composite(w, v, png_ptr->trans_alpha[i], back_1.red); +- palette[i].red = png_ptr->gamma_from_1[w]; ++ component = png_ptr->gamma_to_1[palette[i].red]; ++ component = ++ (component * png_ptr->trans_alpha[i] + 128) / 255; ++ palette[i].red = png_ptr->gamma_from_1[component]; + +- v = png_ptr->gamma_to_1[palette[i].green]; +- png_composite(w, v, png_ptr->trans_alpha[i], back_1.green); +- palette[i].green = png_ptr->gamma_from_1[w]; ++ component = png_ptr->gamma_to_1[palette[i].green]; ++ component = ++ (component * png_ptr->trans_alpha[i] + 128) / 255; ++ palette[i].green = png_ptr->gamma_from_1[component]; + +- v = png_ptr->gamma_to_1[palette[i].blue]; +- png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue); +- palette[i].blue = png_ptr->gamma_from_1[w]; ++ component = png_ptr->gamma_to_1[palette[i].blue]; ++ component = ++ (component * png_ptr->trans_alpha[i] + 128) / 255; ++ palette[i].blue = png_ptr->gamma_from_1[component]; ++ } ++ else ++ { ++ /* Composite with background color: ++ * component = ++ * alpha * component + (1 - alpha) * background ++ */ ++ png_byte v, w; ++ ++ v = png_ptr->gamma_to_1[palette[i].red]; ++ png_composite(w, v, ++ png_ptr->trans_alpha[i], back_1.red); ++ palette[i].red = png_ptr->gamma_from_1[w]; ++ ++ v = png_ptr->gamma_to_1[palette[i].green]; ++ png_composite(w, v, ++ png_ptr->trans_alpha[i], back_1.green); ++ palette[i].green = png_ptr->gamma_from_1[w]; ++ ++ v = png_ptr->gamma_to_1[palette[i].blue]; ++ png_composite(w, v, ++ png_ptr->trans_alpha[i], back_1.blue); ++ palette[i].blue = png_ptr->gamma_from_1[w]; ++ } + } + } + else diff --git a/meta/recipes-multimedia/libpng/libpng_1.6.39.bb b/meta/recipes-multimedia/libpng/libpng_1.6.39.bb index cc35e7a725..efb8eba372 100644 --- a/meta/recipes-multimedia/libpng/libpng_1.6.39.bb +++ b/meta/recipes-multimedia/libpng/libpng_1.6.39.bb @@ -17,6 +17,7 @@ SRC_URI = "\ file://CVE-2025-64505-02.patch \ file://CVE-2025-64505-03.patch \ file://CVE-2025-64506.patch \ + file://CVE-2025-64720.patch \ " SRC_URI[sha256sum] = "1f4696ce70b4ee5f85f1e1623dc1229b210029fa4b7aee573df3e2ba7b036937"