iconv: Accept redundant shift sequences in IBM1364 [BZ #26224]

The IBM1364, IBM1371, IBM1388, IBM1390 and IBM1399 character sets
share converter logic (iconvdata/ibm1364.c) which would reject
redundant shift sequences when processing input in these character
sets.  This led to a hang in the iconv program (CVE-2020-27618).

This commit adjusts the converter to ignore redundant shift sequences
and adds test cases for iconv_prog hangs that would be triggered upon
their rejection.  This brings the implementation in line with other
converters that also ignore redundant shift sequences (e.g. IBM930
etc., fixed in commit 692de4b3960d).

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 9a99c682144bdbd40792ebf822fe9264e0376fb5)

diff --git a/NEWS b/NEWS
index cc36b41dbaa94ae15bc40fe4a85bb2c9bd253bd2..95d69cd07eedcdf732c2961f05f5cb6279cbad23 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -92,6 +92,10 @@ Security related changes:
   corruption when they were passed a pseudo-zero argument.  Reported by Guido
   Vranken / ForAllSecure Mayhem.
 
+  CVE-2020-27618: An infinite loop has been fixed in the iconv program when
+  invoked with input containing redundant shift sequences in the IBM1364,
+  IBM1371, IBM1388, IBM1390, or IBM1399 character sets.
+
 The following bugs are resolved with this release:
 
   [6889] 'PWD' mentioned but not specified
@@ -183,6 +187,8 @@ The following bugs are resolved with this release:
   [25423] Array overflow in backtrace on powerpc
   [25487] sinl() stack corruption from crafted input (CVE-2020-10029)
   [25620] libc: Signed comparison vulnerability in the ARMv7 memcpy() (CVE-2020-6096)
+  [26224] iconv hangs when converting some invalid inputs from several IBM
+    character sets (CVE-2020-27618)
   [26383] bind_textdomain_codeset doesn't accept //TRANSLIT anymore
 
 \f

diff --git a/iconv/tst-iconv_prog.sh b/iconv/tst-iconv_prog.sh
index 8298136b7f45d8554ca074825e306be08d18a008..d8db7b335c1fcca23e71b320510711379c3e9637 100644 (file)
--- a/iconv/tst-iconv_prog.sh
+++ b/iconv/tst-iconv_prog.sh
@@ -102,12 +102,16 @@ hangarray=(
 "\x00\x80;-c;IBM1161;UTF-8//TRANSLIT//IGNORE"
 "\x00\xdb;-c;IBM1162;UTF-8//TRANSLIT//IGNORE"
 "\x00\x70;-c;IBM12712;UTF-8//TRANSLIT//IGNORE"
-# These are known hangs that are yet to be fixed:
-# "\x00\x0f;-c;IBM1364;UTF-8"
-# "\x00\x0f;-c;IBM1371;UTF-8"
-# "\x00\x0f;-c;IBM1388;UTF-8"
-# "\x00\x0f;-c;IBM1390;UTF-8"
-# "\x00\x0f;-c;IBM1399;UTF-8"
+"\x00\x0f;-c;IBM1364;UTF-8"
+"\x0e\x0e;-c;IBM1364;UTF-8"
+"\x00\x0f;-c;IBM1371;UTF-8"
+"\x0e\x0e;-c;IBM1371;UTF-8"
+"\x00\x0f;-c;IBM1388;UTF-8"
+"\x0e\x0e;-c;IBM1388;UTF-8"
+"\x00\x0f;-c;IBM1390;UTF-8"
+"\x0e\x0e;-c;IBM1390;UTF-8"
+"\x00\x0f;-c;IBM1399;UTF-8"
+"\x0e\x0e;-c;IBM1399;UTF-8"
 "\x00\x53;-c;IBM16804;UTF-8//TRANSLIT//IGNORE"
 "\x00\x41;-c;IBM274;UTF-8//TRANSLIT//IGNORE"
 "\x00\x41;-c;IBM275;UTF-8//TRANSLIT//IGNORE"

diff --git a/iconvdata/ibm1364.c b/iconvdata/ibm1364.c
index b833273aa83a7f483062a6a5b7f5504bf2d6a800..27900c4307cd0301d90c5fa80ff7e09de29f73e9 100644 (file)
--- a/iconvdata/ibm1364.c
+++ b/iconvdata/ibm1364.c
@@ -157,24 +157,14 @@ enum
                                                                              \
     if (__builtin_expect (ch, 0) == SO)                                              \
       {                                                                              \
-       /* Shift OUT, change to DBCS converter.  */                           \
-       if (curcs == db)                                                      \
-         {                                                                   \
-           result = __GCONV_ILLEGAL_INPUT;                                   \
-           break;                                                            \
-         }                                                                   \
+       /* Shift OUT, change to DBCS converter (redundant escape okay).  */   \
        curcs = db;                                                           \
        ++inptr;                                                              \
        continue;                                                             \
       }                                                                              \
     if (__builtin_expect (ch, 0) == SI)                                              \
       {                                                                              \
-       /* Shift IN, change to SBCS converter.  */                            \
-       if (curcs == sb)                                                      \
-         {                                                                   \
-           result = __GCONV_ILLEGAL_INPUT;                                   \
-           break;                                                            \
-         }                                                                   \
+       /* Shift IN, change to SBCS converter (redundant escape okay).  */    \
        curcs = sb;                                                           \
        ++inptr;                                                              \
        continue;                                                             \