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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Darren Kenny <darren.kenny@oracle.com>
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Date: Thu, 5 Nov 2020 10:57:14 +0000
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Subject: [PATCH] gnulib/regexec: Fix possible null-dereference
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It appears to be possible that the mctx->state_log field may be NULL,
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and the name of this function, clean_state_log_if_needed(), suggests
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that it should be checking that it is valid to be cleaned before
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assuming that it does.
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Fixes: CID 86720
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Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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 grub-core/gnulib/regexec.c                    |  3 +++
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 conf/Makefile.extra-dist                      |  1 +
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 grub-core/gnulib-fix-regexec-null-deref.patch | 12 ++++++++++++
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 3 files changed, 16 insertions(+)
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 create mode 100644 grub-core/gnulib-fix-regexec-null-deref.patch
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diff --git a/grub-core/gnulib/regexec.c b/grub-core/gnulib/regexec.c
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index fdc178e07a4..1e4cb2df4e3 100644
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--- a/grub-core/gnulib/regexec.c
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+++ b/grub-core/gnulib/regexec.c
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@@ -1754,6 +1754,9 @@ clean_state_log_if_needed (re_match_context_t *mctx, Idx next_state_log_idx)
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 {
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   Idx top = mctx->state_log_top;
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+  if (mctx->state_log == NULL)
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+    return REG_NOERROR;
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+
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   if ((next_state_log_idx >= mctx->input.bufs_len
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        && mctx->input.bufs_len < mctx->input.len)
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       || (next_state_log_idx >= mctx->input.valid_len
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diff --git a/conf/Makefile.extra-dist b/conf/Makefile.extra-dist
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index c3506afe792..60d9f564236 100644
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--- a/conf/Makefile.extra-dist
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+++ b/conf/Makefile.extra-dist
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@@ -28,6 +28,7 @@ EXTRA_DIST += grub-core/genemuinitheader.sh
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 EXTRA_DIST += grub-core/gnulib-fix-null-deref.diff
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 EXTRA_DIST += grub-core/gnulib-fix-null-state-deref.patch
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+EXTRA_DIST += grub-core/gnulib-fix-regexec-null-deref.patch
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 EXTRA_DIST += grub-core/gnulib-fix-uninit-structure.patch
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 EXTRA_DIST += grub-core/gnulib-fix-unused-value.patch
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 EXTRA_DIST += grub-core/gnulib-fix-width.diff
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diff --git a/grub-core/gnulib-fix-regexec-null-deref.patch b/grub-core/gnulib-fix-regexec-null-deref.patch
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new file mode 100644
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index 00000000000..db6dac9c9e3
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--- /dev/null
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+++ b/grub-core/gnulib-fix-regexec-null-deref.patch
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@@ -0,0 +1,12 @@
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+--- a/lib/regexec.c	2020-10-21 14:25:35.310195912 +0000
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++++ b/lib/regexec.c	2020-11-05 10:55:09.621542984 +0000
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+@@ -1692,6 +1692,9 @@
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+ {
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+   Idx top = mctx->state_log_top;
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+
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++  if (mctx->state_log == NULL)
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++    return REG_NOERROR;
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++
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+   if ((next_state_log_idx >= mctx->input.bufs_len
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+        && mctx->input.bufs_len < mctx->input.len)
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+       || (next_state_log_idx >= mctx->input.valid_len