Bug#883792: libxcursor: diff for NMU version 1:1.1.14-3.1
Control: tags 883792 + pending
Dear maintainer,
I've prepared an NMU for libxcursor (versioned as 1:1.1.14-3.1) and
uploaded it to DELAYED/2. Please feel free to tell me if I
should delay it longer.
Regards,
Salvatore
diff -Nru libxcursor-1.1.14/debian/changelog libxcursor-1.1.14/debian/changelog
--- libxcursor-1.1.14/debian/changelog 2017-08-24 08:55:44.000000000 +0200
+++ libxcursor-1.1.14/debian/changelog 2017-12-09 08:45:47.000000000 +0100
@@ -1,3 +1,11 @@
+libxcursor (1:1.1.14-3.1) unstable; urgency=medium
+
+ * Non-maintainer upload.
+ * Fix heap overflows when parsing malicious files (CVE-2017-16612)
+ (Closes: #883792)
+
+ -- Salvatore Bonaccorso <carnil@debian.org> Sat, 09 Dec 2017 08:45:47 +0100
+
libxcursor (1:1.1.14-3) unstable; urgency=medium
* Team upload.
diff -Nru libxcursor-1.1.14/debian/patches/Fix-heap-overflows-when-parsing-malicious-files.-CVE.patch libxcursor-1.1.14/debian/patches/Fix-heap-overflows-when-parsing-malicious-files.-CVE.patch
--- libxcursor-1.1.14/debian/patches/Fix-heap-overflows-when-parsing-malicious-files.-CVE.patch 1970-01-01 01:00:00.000000000 +0100
+++ libxcursor-1.1.14/debian/patches/Fix-heap-overflows-when-parsing-malicious-files.-CVE.patch 2017-12-09 08:45:47.000000000 +0100
@@ -0,0 +1,75 @@
+From: Tobias Stoeckmann <tobias@stoeckmann.org>
+Date: Sat, 21 Oct 2017 23:47:52 +0200
+Subject: Fix heap overflows when parsing malicious files. (CVE-2017-16612)
+Origin: https://cgit.freedesktop.org/xorg/lib/libXcursor/commit?id=4794b5dd34688158fb51a2943032569d3780c4b8
+Bug-Debian: https://bugs.debian.org/883792
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2017-16612
+
+It is possible to trigger heap overflows due to an integer overflow
+while parsing images and a signedness issue while parsing comments.
+
+The integer overflow occurs because the chosen limit 0x10000 for
+dimensions is too large for 32 bit systems, because each pixel takes
+4 bytes. Properly chosen values allow an overflow which in turn will
+lead to less allocated memory than needed for subsequent reads.
+
+The signedness bug is triggered by reading the length of a comment
+as unsigned int, but casting it to int when calling the function
+XcursorCommentCreate. Turning length into a negative value allows the
+check against XCURSOR_COMMENT_MAX_LEN to pass, and the following
+addition of sizeof (XcursorComment) + 1 makes it possible to allocate
+less memory than needed for subsequent reads.
+
+Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
+Reviewed-by: Matthieu Herrb <matthieu@herrb.eu>
+---
+ src/file.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/src/file.c b/src/file.c
+index 43163c2..da16277 100644
+--- a/src/file.c
++++ b/src/file.c
+@@ -29,6 +29,11 @@ XcursorImageCreate (int width, int height)
+ {
+ XcursorImage *image;
+
++ if (width < 0 || height < 0)
++ return NULL;
++ if (width > XCURSOR_IMAGE_MAX_SIZE || height > XCURSOR_IMAGE_MAX_SIZE)
++ return NULL;
++
+ image = malloc (sizeof (XcursorImage) +
+ width * height * sizeof (XcursorPixel));
+ if (!image)
+@@ -101,7 +106,7 @@ XcursorCommentCreate (XcursorUInt comment_type, int length)
+ {
+ XcursorComment *comment;
+
+- if (length > XCURSOR_COMMENT_MAX_LEN)
++ if (length < 0 || length > XCURSOR_COMMENT_MAX_LEN)
+ return NULL;
+
+ comment = malloc (sizeof (XcursorComment) + length + 1);
+@@ -448,7 +453,8 @@ _XcursorReadImage (XcursorFile *file,
+ if (!_XcursorReadUInt (file, &head.delay))
+ return NULL;
+ /* sanity check data */
+- if (head.width >= 0x10000 || head.height > 0x10000)
++ if (head.width > XCURSOR_IMAGE_MAX_SIZE ||
++ head.height > XCURSOR_IMAGE_MAX_SIZE)
+ return NULL;
+ if (head.width == 0 || head.height == 0)
+ return NULL;
+@@ -457,6 +463,8 @@ _XcursorReadImage (XcursorFile *file,
+
+ /* Create the image and initialize it */
+ image = XcursorImageCreate (head.width, head.height);
++ if (image == NULL)
++ return NULL;
+ if (chunkHeader.version < image->version)
+ image->version = chunkHeader.version;
+ image->size = chunkHeader.subtype;
+--
+2.15.1
+
diff -Nru libxcursor-1.1.14/debian/patches/series libxcursor-1.1.14/debian/patches/series
--- libxcursor-1.1.14/debian/patches/series 2017-08-24 08:55:44.000000000 +0200
+++ libxcursor-1.1.14/debian/patches/series 2017-12-09 08:45:47.000000000 +0100
@@ -1 +1,2 @@
autogen.sh-install
+Fix-heap-overflows-when-parsing-malicious-files.-CVE.patch
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