forked from rpms/glibc
110 lines
3.5 KiB
Diff
110 lines
3.5 KiB
Diff
commit f7a79879c0b2bef0dadd6caaaeeb0d26423e04e5
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Author: Siddhesh Poyarekar <siddhesh@sourceware.org>
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Date: Thu Jan 13 11:28:36 2022 +0530
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realpath: Set errno to ENAMETOOLONG for result larger than PATH_MAX [BZ #28770]
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realpath returns an allocated string when the result exceeds PATH_MAX,
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which is unexpected when its second argument is not NULL. This results
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in the second argument (resolved) being uninitialized and also results
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in a memory leak since the caller expects resolved to be the same as the
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returned value.
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Return NULL and set errno to ENAMETOOLONG if the result exceeds
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PATH_MAX. This fixes [BZ #28770], which is CVE-2021-3998.
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Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
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(cherry picked from commit ee8d5e33adb284601c00c94687bc907e10aec9bb)
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diff --git a/stdlib/Makefile b/stdlib/Makefile
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index 9bb5c221e8be3288..a4ac30d1f6359561 100644
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--- a/stdlib/Makefile
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+++ b/stdlib/Makefile
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@@ -109,6 +109,7 @@ tests := \
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tst-random \
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tst-random2 \
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tst-realpath \
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+ tst-realpath-toolong \
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tst-secure-getenv \
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tst-setcontext \
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tst-setcontext2 \
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diff --git a/stdlib/canonicalize.c b/stdlib/canonicalize.c
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index 698f9ede25570ef2..7a23a51b3a395eb3 100644
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--- a/stdlib/canonicalize.c
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+++ b/stdlib/canonicalize.c
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@@ -400,8 +400,16 @@ realpath_stk (const char *name, char *resolved,
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error:
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*dest++ = '\0';
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- if (resolved != NULL && dest - rname <= get_path_max ())
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- rname = strcpy (resolved, rname);
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+ if (resolved != NULL)
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+ {
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+ if (dest - rname <= get_path_max ())
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+ rname = strcpy (resolved, rname);
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+ else
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+ {
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+ failed = true;
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+ __set_errno (ENAMETOOLONG);
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+ }
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+ }
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error_nomem:
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scratch_buffer_free (&extra_buffer);
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diff --git a/stdlib/tst-realpath-toolong.c b/stdlib/tst-realpath-toolong.c
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new file mode 100644
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index 0000000000000000..8bed772460b37571
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--- /dev/null
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+++ b/stdlib/tst-realpath-toolong.c
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@@ -0,0 +1,49 @@
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+/* Verify that realpath returns NULL with ENAMETOOLONG if the result exceeds
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+ NAME_MAX.
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+ Copyright The GNU Toolchain Authors.
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+ This file is part of the GNU C Library.
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+
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+ The GNU C Library is free software; you can redistribute it and/or
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+ modify it under the terms of the GNU Lesser General Public
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+ License as published by the Free Software Foundation; either
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+ version 2.1 of the License, or (at your option) any later version.
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+
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+ The GNU C Library is distributed in the hope that it will be useful,
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+ but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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+ Lesser General Public License for more details.
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+
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+ You should have received a copy of the GNU Lesser General Public
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+ License along with the GNU C Library; if not, see
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+ <https://www.gnu.org/licenses/>. */
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+
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+#include <errno.h>
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+#include <limits.h>
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+#include <stdlib.h>
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+#include <string.h>
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+#include <unistd.h>
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+#include <support/check.h>
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+#include <support/temp_file.h>
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+#include <sys/types.h>
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+#include <sys/stat.h>
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+
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+#define BASENAME "tst-realpath-toolong."
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+
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+int
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+do_test (void)
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+{
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+ char *base = support_create_and_chdir_toolong_temp_directory (BASENAME);
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+
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+ char buf[PATH_MAX + 1];
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+ const char *res = realpath (".", buf);
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+
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+ /* canonicalize.c states that if the real path is >= PATH_MAX, then
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+ realpath returns NULL and sets ENAMETOOLONG. */
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+ TEST_VERIFY (res == NULL);
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+ TEST_VERIFY (errno == ENAMETOOLONG);
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+
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+ free (base);
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+ return 0;
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+}
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+
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+#include <support/test-driver.c>
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