From: Mark Wielaard <mark@klomp.org>
To: elfutils-devel@sourceware.org
Cc: Mark Wielaard <mark@klomp.org>
Subject: [COMMITTED] readelf: Fix use-after-free ebl pointer issue
Date: Fri, 3 Mar 2023 14:26:31 +0100 [thread overview]
Message-ID: <20230303132631.219940-1-mark@klomp.org> (raw)
With -flto gcc 13 sees that we use the ebl pointer after closing and
freeing it.
In function ‘process_elf_file’,
inlined from ‘process_dwflmod’ at readelf.c:818:3:
readelf.c:1070:6: error: pointer ‘ebl_18’ used after ‘free’ [-Werror=use-after-free]
1070 | if (pure_ebl != ebl)
| ^
In function ‘ebl_closebackend’,
inlined from ‘process_elf_file’ at readelf.c:1068:3,
inlined from ‘process_dwflmod’ at readelf.c:818:3:
../libebl/eblclosebackend.c:47:7: note: call to ‘free’ here
47 | free (ebl);
| ^
Fix by only calling ebl_closebackend after using it in the comparison.
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
src/ChangeLog | 5 +++++
src/readelf.c | 5 +++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/src/ChangeLog b/src/ChangeLog
index 699d98ee..c26dafdd 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2023-03-03 Mark Wielaard <mark@klomp.org>
+
+ * readelf (process_elf_file): ebl_closebackend only after
+ comparing ebl pointer.
+
2023-02-12 Mark Wielaard <mark@klomp.org>
* readelf.c (print_attributes): Add comment about check.
diff --git a/src/readelf.c b/src/readelf.c
index 0f13874f..6950204e 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -1065,13 +1065,14 @@ process_elf_file (Dwfl_Module *dwflmod, int fd)
if (print_string_sections)
print_strings (ebl);
- ebl_closebackend (ebl);
-
if (pure_ebl != ebl)
{
+ ebl_closebackend (ebl);
ebl_closebackend (pure_ebl);
elf_end (pure_elf);
}
+ else
+ ebl_closebackend (ebl);
}
--
2.39.2
reply other threads:[~2023-03-03 13:26 UTC|newest]
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