gnu: ghostscript: Fix CVE-2020-15900.

* gnu/packages/patches/ghostscript-CVE-2020-15900.patch: New file.
* gnu/local.mk (dist_patch_DATA): Adjust accordingly.
* gnu/packages/ghostscript.scm (ghostscript)[source](patches): Add it.

3 files changed, 38 insertions, 0 deletions

diff --git a/gnu/local.mk b/gnu/local.mk
index 97dd9a74d00..7f0b69cacf9 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1055,6 +1055,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/ghc-monad-par-fix-tests.patch            \
   %D%/packages/patches/ghc-pandoc-fix-html-tests.patch          \
   %D%/packages/patches/ghc-pandoc-fix-latex-test.patch          \
+  %D%/packages/patches/ghostscript-CVE-2020-15900.patch         \
   %D%/packages/patches/ghostscript-freetype-compat.patch        \
   %D%/packages/patches/ghostscript-no-header-id.patch           \
   %D%/packages/patches/ghostscript-no-header-uuid.patch         \
diff --git a/gnu/packages/ghostscript.scm b/gnu/packages/ghostscript.scm
index b132fba7eb7..03a516dc522 100644
--- a/gnu/packages/ghostscript.scm
+++ b/gnu/packages/ghostscript.scm
@@ -171,6 +171,7 @@ printing, and psresize, for adjusting page sizes.")
          (base32
           "0z1w42y2jmcpl2m1l3z0sfii6zmvzcwcgzn6bydklia6ig7jli2p"))
         (patches (search-patches "ghostscript-freetype-compat.patch"
+                                 "ghostscript-CVE-2020-15900.patch"
                                  "ghostscript-no-header-creationdate.patch"
                                  "ghostscript-no-header-id.patch"
                                  "ghostscript-no-header-uuid.patch"))
diff --git a/gnu/packages/patches/ghostscript-CVE-2020-15900.patch b/gnu/packages/patches/ghostscript-CVE-2020-15900.patch
new file mode 100644
index 00000000000..b6658d7c7f6
--- /dev/null
+++ b/gnu/packages/patches/ghostscript-CVE-2020-15900.patch
@@ -0,0 +1,36 @@
+Fix CVE-2020-15900.
+
+https://cve.circl.lu/cve/CVE-2020-15900
+https://artifex.com/security-advisories/CVE-2020-15900
+
+Taken from upstream:
+https://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=5d499272b95a6b890a1397e11d20937de000d31b
+
+diff --git a/psi/zstring.c b/psi/zstring.c
+--- a/psi/zstring.c
++++ b/psi/zstring.c
+@@ -142,13 +142,18 @@ search_impl(i_ctx_t *i_ctx_p, bool forward)
+     return 0;
+ found:
+     op->tas.type_attrs = op1->tas.type_attrs;
+-    op->value.bytes = ptr;
+-    r_set_size(op, size);
++    op->value.bytes = ptr;                             /* match */
++    op->tas.rsize = size;                              /* match */
+     push(2);
+-    op[-1] = *op1;
+-    r_set_size(op - 1, ptr - op[-1].value.bytes);
+-    op1->value.bytes = ptr + size;
+-    r_set_size(op1, count + (!forward ? (size - 1) : 0));
++    op[-1] = *op1;                                     /* pre */
++    op[-3].value.bytes = ptr + size;                   /* post */
++    if (forward) {
++        op[-1].tas.rsize = ptr - op[-1].value.bytes;   /* pre */
++        op[-3].tas.rsize = count;                      /* post */
++    } else {
++        op[-1].tas.rsize = count;                      /* pre */
++        op[-3].tas.rsize -= count + size;              /* post */
++    }
+     make_true(op);
+     return 0;
+ }