From 71f0ac4d01a9fdf96bed4c18e749a0e6604df63d Mon Sep 17 00:00:00 2001 From: RHEL Packaging Agent Date: Wed, 22 Jul 2026 16:21:43 +0000 Subject: [PATCH] Fix CVE-2026-58013: memcmp buffer over-read in giochannel Backport upstream fix (commit 9f557746c52a) for CVE-2026-58013 to mingw-glib2 on c8s. The patch adds a bounds check before the memcmp() call in glib/giochannel.c to prevent a buffer over-read when using line terminators longer than 1 byte. A unit test for the fix is also included. CVE: CVE-2026-58013 Upstream patches: - https://gitlab.gnome.org/GNOME/glib/-/commit/9f557746c52ae2a62fd5929f532b77024a18abe2.patch Resolves: RHEL-212234 This commit was backported by Ymir, a Red Hat Enterprise Linux software maintenance AI agent. Assisted-by: Ymir --- mingw-glib2-2.70.1-CVE-2026-58013.patch | 120 ++++++++++++++++++++++++ mingw-glib2.spec | 10 +- 2 files changed, 129 insertions(+), 1 deletion(-) create mode 100644 mingw-glib2-2.70.1-CVE-2026-58013.patch diff --git a/mingw-glib2-2.70.1-CVE-2026-58013.patch b/mingw-glib2-2.70.1-CVE-2026-58013.patch new file mode 100644 index 0000000..b0afd38 --- /dev/null +++ b/mingw-glib2-2.70.1-CVE-2026-58013.patch @@ -0,0 +1,120 @@ +From 5e8a44975bddd21a762e58c6717f841e90594f03 Mon Sep 17 00:00:00 2001 +From: Philip Withnall +Date: Tue, 28 Apr 2026 16:45:14 +0100 +Subject: [PATCH] giochannel: Fix memcmp() off the end of the buffer with long + terminators +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +If the line terminator is longer than a single byte, and the current +line extends to the end of the buffer, and the buffer (which is a +`GString`) is near a power of two in length (as that’s how `GString`s +are allocated) it’s possible for the `memcmp()` which checks the +terminator to read off the end of the string buffer. + +Fix that by checking the terminator length against the last character +before calling `memcmp()`. Add a unit test. + +Spotted by linhlhq as #YWH-PGM9867-199. The fix is theirs (validated by +me), and the unit test is adapted from their proof of concept. + +Signed-off-by: Philip Withnall +Fixes: #3925 +--- + glib/giochannel.c | 3 ++- + glib/tests/io-channel.c | 60 +++++++++++++++++++++++++++++++++++++++++ + 2 files changed, 62 insertions(+), 1 deletion(-) + +diff --git a/glib/giochannel.c b/glib/giochannel.c +index e93c4b458..66b68e645 100644 +--- a/glib/giochannel.c ++++ b/glib/giochannel.c +@@ -1830,7 +1830,8 @@ read_again: + { + if (channel->line_term) + { +- if (memcmp (channel->line_term, nextchar, line_term_len) == 0) ++ if ((size_t) (lastchar - nextchar) >= line_term_len && ++ memcmp (channel->line_term, nextchar, line_term_len) == 0) + { + line_length = nextchar - use_buf->str; + got_term_len = line_term_len; +diff --git a/glib/tests/io-channel.c b/glib/tests/io-channel.c +index 4a1b10876..c619fb00f 100644 +--- a/glib/tests/io-channel.c ++++ b/glib/tests/io-channel.c +@@ -69,6 +69,65 @@ test_read_line_embedded_nuls (void) + g_free (filename); + } + ++static void ++test_read_line_long_terminator (void) ++{ ++ uint8_t *test_data = NULL; ++ size_t test_data_len = 0; ++ int fd; ++ char *filename = NULL; ++ GIOChannel *channel = NULL; ++ GError *local_error = NULL; ++ char *line = NULL; ++ size_t line_length, terminator_pos; ++ const char *line_term; ++ int line_term_length; ++ GIOStatus status; ++ ++ g_test_summary ("Test that reading a line when using a long terminator doesn’t over-read the buffer."); ++ g_test_bug ("https://gitlab.gnome.org/GNOME/glib/-/work_items/3925"); ++ ++ /* Write out a temporary file containing 2047 bytes. This is enough to make it ++ * near the length of the GString buffer when read back in. */ ++ fd = g_file_open_tmp ("glib-test-io-channel-XXXXXX", &filename, &local_error); ++ g_assert_no_error (local_error); ++ g_close (g_steal_fd (&fd), NULL); ++ ++ test_data_len = 2047; ++ test_data = g_malloc (test_data_len); ++ memset (test_data, 'M', test_data_len); ++ g_file_set_contents (filename, (const gchar *) test_data, test_data_len, &local_error); ++ g_assert_no_error (local_error); ++ ++ /* Create the channel. */ ++ channel = g_io_channel_new_file (filename, "r", &local_error); ++ g_assert_no_error (local_error); ++ ++ /* Use a long line terminator so it could potentially over-read the end of the buffer. */ ++ g_io_channel_set_line_term (channel, "DEADBEEF", 8); ++ ++ line_term = g_io_channel_get_line_term (channel, &line_term_length); ++ g_assert_cmpstr (line_term, ==, "DEADBEEF"); ++ g_assert_cmpint (line_term_length, ==, 8); ++ ++ g_io_channel_set_encoding (channel, "UTF-8", &local_error); ++ g_assert_no_error (local_error); ++ ++ status = g_io_channel_read_line (channel, &line, &line_length, ++ &terminator_pos, &local_error); ++ g_assert_no_error (local_error); ++ g_assert_cmpint (status, ==, G_IO_STATUS_NORMAL); ++ g_assert_cmpuint (line_length, ==, 2047); ++ g_assert_cmpuint (terminator_pos, ==, 2047); ++ g_assert_cmpmem (line, line_length, test_data, test_data_len); ++ ++ g_free (line); ++ g_io_channel_unref (channel); ++ g_free (test_data); ++ g_unlink (filename); ++ g_free (filename); ++} ++ + int + main (int argc, + char *argv[]) +@@ -76,6 +135,7 @@ main (int argc, + g_test_init (&argc, &argv, NULL); + + g_test_add_func ("/io-channel/read-line/embedded-nuls", test_read_line_embedded_nuls); ++ g_test_add_func ("/io-channel/read-line/long-terminator", test_read_line_long_terminator); + + return g_test_run (); + } diff --git a/mingw-glib2.spec b/mingw-glib2.spec index d1eff2f..d5b0c01 100644 --- a/mingw-glib2.spec +++ b/mingw-glib2.spec @@ -5,7 +5,7 @@ Name: mingw-glib2 Version: 2.70.1 -Release: 6%{?dist} +Release: 7%{?dist} Summary: MinGW Windows GLib2 library License: LGPLv2+ @@ -71,6 +71,9 @@ Patch6: mingw-glib2-2.70.1-CVE-2025-14087.patch # https://gitlab.gnome.org/GNOME/glib/-/issues/3918 Patch7: mingw-glib2-2.70.1-CVE-2026-58012.patch +# https://gitlab.gnome.org/GNOME/glib/-/work_items/3925 +Patch8: mingw-glib2-2.70.1-CVE-2026-58013.patch + %description MinGW Windows Glib2 library. @@ -123,6 +126,7 @@ Static version of the MinGW Windows GLib2 library. %patch5 -p1 %patch6 -p1 %patch7 -p1 +%patch8 -p1 %build %mingw_meson --default-library=both \ @@ -300,6 +304,10 @@ find $RPM_BUILD_ROOT -name "*.la" -delete %changelog +* Wed Jul 22 2026 RHEL Packaging Agent - 2.70.1-7 +- Fix CVE-2026-58013: memcmp buffer over-read in giochannel + Resolves: RHEL-212234 + * Wed Jul 22 2026 RHEL Packaging Agent - 2.70.1-6 - Fix CVE-2026-58012: buffer overflow in gregex substitutions Resolves: RHEL-212200