From 32cba115e935a5d01b212205b791d8c16617515e Mon Sep 17 00:00:00 2001 From: Vijay Anusuri Date: Sat, 12 Sep 2026 17:14:28 +0530 Subject: [PATCH] libxfont: Fix CVE-2026-56001 Pick patch according to [2] [1] https://nvd.nist.gov/vuln/detail/CVE-2026-56001 [2] https://security-tracker.debian.org/tracker/CVE-2026-56001 (From OE-Core rev: 5a5af4e7c55a26951827622143831d89db2f4ad5) Signed-off-by: Vijay Anusuri Signed-off-by: Yoann Congal Signed-off-by: Paul Barker --- .../xorg-lib/libxfont/CVE-2026-56001.patch | 87 +++++++++++++++++++ .../xorg-lib/libxfont_1.5.4.bb | 3 + 2 files changed, 90 insertions(+) create mode 100644 meta/recipes-graphics/xorg-lib/libxfont/CVE-2026-56001.patch diff --git a/meta/recipes-graphics/xorg-lib/libxfont/CVE-2026-56001.patch b/meta/recipes-graphics/xorg-lib/libxfont/CVE-2026-56001.patch new file mode 100644 index 0000000000..1de7f3e037 --- /dev/null +++ b/meta/recipes-graphics/xorg-lib/libxfont/CVE-2026-56001.patch @@ -0,0 +1,87 @@ +From be0b08e2d354138d3222b4490e2a77c6ee42f778 Mon Sep 17 00:00:00 2001 +From: Peter Hutterer +Date: Mon, 1 Jun 2026 16:46:10 +1000 +Subject: [PATCH] bitscale: fix integer overflow in BitmapScaleBitmaps + bytestoalloc + +bytestoalloc is declared as unsigned int (32-bit). When the sum of +per-glyph byte counts exceeds 2^32, the value wraps around and calloc() +allocates a buffer that is too small. The subsequent ScaleBitmap loop +then writes past the end of the allocated buffer. + +Change bytestoalloc from unsigned int to size_t to match the actual +allocation size type, and add an explicit overflow check in the +accumulation loop to bail out if the total would exceed SIZE_MAX. + +This vulnerability was discovered by: +Anonymous working with TrendAI Zero Day Initiative + +CVE-2026-56001/ZDI-CAN-30558 + +Assisted-by: Claude:claude-opus-4-6 +Signed-off-by: Peter Hutterer +Part-of: + +Note: 'SIZE_MAX' is defined in header ''. Add '#include +' to fix build failure. + +Upstream-Status: Backport [import from debian libxfont1 1.5.2-4+deb9u1 +Upstream commit https://gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/be0b08e2d354138d3222b4490e2a77c6ee42f778] +CVE: CVE-2026-56001 +Signed-off-by: Vijay Anusuri +--- + src/bitmap/bitscale.c | 24 +++++++++++++++++++++--- + 1 file changed, 21 insertions(+), 3 deletions(-) + +diff --git a/src/bitmap/bitscale.c b/src/bitmap/bitscale.c +index 13ed924..32144d6 100644 +--- a/src/bitmap/bitscale.c ++++ b/src/bitmap/bitscale.c +@@ -38,6 +38,7 @@ from The Open Group. + #include + #include + #include ++#include + + #ifndef MAX + #define MAX(a,b) (((a)>(b)) ? a : b) +@@ -1459,7 +1460,7 @@ BitmapScaleBitmaps(FontPtr pf, /* scaled font */ + opci; + FontInfoPtr pfi; + int glyph; +- unsigned bytestoalloc = 0; ++ size_t bytestoalloc = 0; + int firstCol, lastCol, firstRow, lastRow; + + double xform[4], inv_xform[4]; +@@ -1486,8 +1487,25 @@ BitmapScaleBitmaps(FontPtr pf, /* scaled font */ + glyph = pf->glyph; + for (i = 0; i < nchars; i++) + { +- if ((pci = ACCESSENCODING(bitmapFont->encoding, i))) +- bytestoalloc += BYTES_FOR_GLYPH(pci, glyph); ++ if ((pci = ACCESSENCODING(bitmapFont->encoding, i))) { ++ size_t glyphsize = BYTES_FOR_GLYPH(pci, glyph); ++ if (bytestoalloc > SIZE_MAX - glyphsize) { ++ fprintf(stderr, ++ "Error: bitmap allocation overflow for scaled font\n"); ++ goto bail; ++ } ++ bytestoalloc += glyphsize; ++ } ++ } ++ ++ /* Reject unreasonably large bitmap allocations that could result ++ * from malicious fonts with extreme scale factors. 256 MiB is ++ * far beyond any legitimate scaled bitmap font. */ ++#define BITMAP_SCALE_MAX_ALLOC (256 * 1024 * 1024) ++ if (bytestoalloc > BITMAP_SCALE_MAX_ALLOC) { ++ fprintf(stderr, ++ "Error: scaled bitmap size %zu exceeds limit\n", bytestoalloc); ++ goto bail; + } + + /* Do we add the font malloc stuff for VALUE ADDED ? */ +-- +2.43.0 + diff --git a/meta/recipes-graphics/xorg-lib/libxfont_1.5.4.bb b/meta/recipes-graphics/xorg-lib/libxfont_1.5.4.bb index fa6585d6dc..1173794f8d 100644 --- a/meta/recipes-graphics/xorg-lib/libxfont_1.5.4.bb +++ b/meta/recipes-graphics/xorg-lib/libxfont_1.5.4.bb @@ -19,6 +19,9 @@ XORG_EXT = "tar.bz2" BBCLASSEXTEND = "native" +SRC_URI += "file://CVE-2026-56001.patch \ + " + SRC_URI[md5sum] = "16eaf156edd79b68038b6a7c44aa9e9b" SRC_URI[sha256sum] = "1a7f7490774c87f2052d146d1e0e64518d32e6848184a18654e8d0bb57883242"