[Buildroot] [PATCH 1/2] libcroco: add upstream security fixes

Peter Korsgaard peter at korsgaard.com
Tue Apr 25 14:16:59 UTC 2017


These have been added to upstream git after 0.6.12 was released.

CVE-2017-7960 - The cr_input_new_from_uri function in cr-input.c in libcroco
0.6.11 and 0.6.12 allows remote attackers to cause a denial of service
(heap-based buffer over-read) via a crafted CSS file.

CVE-2017-7961 - The cr_tknzr_parse_rgb function in cr-tknzr.c in libcroco
0.6.11 and 0.6.12 has an "outside the range of representable values of type
long" undefined behavior issue, which might allow remote attackers to cause
a denial of service (application crash) or possibly have unspecified other
impact via a crafted CSS file.

For more details, see:
https://blogs.gentoo.org/ago/2017/04/17/libcroco-heap-overflow-and-undefined-behavior/

Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 ...-check-end-of-input-before-reading-a-byte.patch | 62 ++++++++++++++++++++++
 ...02-tknzr-support-only-max-long-rgb-values.patch | 46 ++++++++++++++++
 2 files changed, 108 insertions(+)
 create mode 100644 package/libcroco/0001-input-check-end-of-input-before-reading-a-byte.patch
 create mode 100644 package/libcroco/0002-tknzr-support-only-max-long-rgb-values.patch

diff --git a/package/libcroco/0001-input-check-end-of-input-before-reading-a-byte.patch b/package/libcroco/0001-input-check-end-of-input-before-reading-a-byte.patch
new file mode 100644
index 000000000..831b1a745
--- /dev/null
+++ b/package/libcroco/0001-input-check-end-of-input-before-reading-a-byte.patch
@@ -0,0 +1,62 @@
+From 898e3a8c8c0314d2e6b106809a8e3e93cf9d4394 Mon Sep 17 00:00:00 2001
+From: Ignacio Casal Quinteiro <qignacio at amazon.com>
+Date: Sun, 16 Apr 2017 13:13:43 +0200
+Subject: [PATCH] input: check end of input before reading a byte
+
+Fixes CVE-2017-7960
+
+When reading bytes we weren't check that the index wasn't
+out of bound and this could produce an invalid read which
+could deal to a security bug.
+
+Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
+---
+ src/cr-input.c | 11 +++++++++--
+ 1 file changed, 9 insertions(+), 2 deletions(-)
+
+diff --git a/src/cr-input.c b/src/cr-input.c
+index 49000b1..3b63a88 100644
+--- a/src/cr-input.c
++++ b/src/cr-input.c
+@@ -256,7 +256,7 @@ cr_input_new_from_uri (const gchar * a_file_uri, enum CREncoding a_enc)
+                  *we should  free buf here because it's own by CRInput.
+                  *(see the last parameter of cr_input_new_from_buf().
+                  */
+-                buf = NULL ;
++                buf = NULL;
+         }
+ 
+  cleanup:
+@@ -404,6 +404,8 @@ cr_input_get_nb_bytes_left (CRInput const * a_this)
+ enum CRStatus
+ cr_input_read_byte (CRInput * a_this, guchar * a_byte)
+ {
++        gulong nb_bytes_left = 0;
++
+         g_return_val_if_fail (a_this && PRIVATE (a_this)
+                               && a_byte, CR_BAD_PARAM_ERROR);
+ 
+@@ -413,6 +415,12 @@ cr_input_read_byte (CRInput * a_this, guchar * a_byte)
+         if (PRIVATE (a_this)->end_of_input == TRUE)
+                 return CR_END_OF_INPUT_ERROR;
+ 
++        nb_bytes_left = cr_input_get_nb_bytes_left (a_this);
++
++        if (nb_bytes_left < 1) {
++                return CR_END_OF_INPUT_ERROR;
++        }
++
+         *a_byte = PRIVATE (a_this)->in_buf[PRIVATE (a_this)->next_byte_index];
+ 
+         if (PRIVATE (a_this)->nb_bytes -
+@@ -477,7 +485,6 @@ cr_input_read_char (CRInput * a_this, guint32 * a_char)
+                 if (*a_char == '\n') {
+                         PRIVATE (a_this)->end_of_line = TRUE;
+                 }
+-
+         }
+ 
+         return status;
+-- 
+2.11.0
+
diff --git a/package/libcroco/0002-tknzr-support-only-max-long-rgb-values.patch b/package/libcroco/0002-tknzr-support-only-max-long-rgb-values.patch
new file mode 100644
index 000000000..1a9bcd947
--- /dev/null
+++ b/package/libcroco/0002-tknzr-support-only-max-long-rgb-values.patch
@@ -0,0 +1,46 @@
+From 9ad72875e9f08e4c519ef63d44cdbd94aa9504f7 Mon Sep 17 00:00:00 2001
+From: Ignacio Casal Quinteiro <qignacio at amazon.com>
+Date: Sun, 16 Apr 2017 13:56:09 +0200
+Subject: [PATCH] tknzr: support only max long rgb values
+
+Fixes CVE-2017-7961
+
+This fixes a possible out of bound when reading rgbs which
+are longer than the support MAXLONG
+
+Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
+---
+ src/cr-tknzr.c | 10 ++++++++++
+ 1 file changed, 10 insertions(+)
+
+diff --git a/src/cr-tknzr.c b/src/cr-tknzr.c
+index 1a7cfeb..1548c35 100644
+--- a/src/cr-tknzr.c
++++ b/src/cr-tknzr.c
+@@ -1279,6 +1279,11 @@ cr_tknzr_parse_rgb (CRTknzr * a_this, CRRgb ** a_rgb)
+         status = cr_tknzr_parse_num (a_this, &num);
+         ENSURE_PARSING_COND ((status == CR_OK) && (num != NULL));
+ 
++        if (num->val > G_MAXLONG) {
++                status = CR_PARSING_ERROR;
++                goto error;
++        }
++
+         red = num->val;
+         cr_num_destroy (num);
+         num = NULL;
+@@ -1298,6 +1303,11 @@ cr_tknzr_parse_rgb (CRTknzr * a_this, CRRgb ** a_rgb)
+                 status = cr_tknzr_parse_num (a_this, &num);
+                 ENSURE_PARSING_COND ((status == CR_OK) && (num != NULL));
+ 
++                if (num->val > G_MAXLONG) {
++                        status = CR_PARSING_ERROR;
++                        goto error;
++                }
++
+                 PEEK_BYTE (a_this, 1, &next_bytes[0]);
+                 if (next_bytes[0] == '%') {
+                         SKIP_CHARS (a_this, 1);
+-- 
+2.11.0
+
-- 
2.11.0



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