From: Max Kellermann <max.kellermann@ionos.com>
To: masahiroy@kernel.org, nathan@kernel.org, nicolas@fjasle.eu,
linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Max Kellermann <max.kellermann@ionos.com>
Subject: [PATCH] scripts/mod/modpost: fix null pointer dereference
Date: Thu, 15 Feb 2024 15:13:21 +0100 [thread overview]
Message-ID: <20240215141321.899675-1-max.kellermann@ionos.com> (raw)
If the find_fromsym() call fails and returns NULL, the warn() call
will dereference this NULL pointer and cause the program to crash.
This happened when I tried to build with "test_user_copy" module.
With this fix, it prints lots of warnings like this:
WARNING: modpost: lib/test_user_copy: section mismatch in reference: (unknown)+0x4 (section: .text.fixup) -> (unknown) (section: .init.text)
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
scripts/mod/modpost.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index bf7c4b4b5ff4..6b37039c9e92 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1050,7 +1050,9 @@ static void default_mismatch_handler(const char *modname, struct elf_info *elf,
sec_mismatch_count++;
warn("%s: section mismatch in reference: %s+0x%x (section: %s) -> %s (section: %s)\n",
- modname, fromsym, (unsigned int)(faddr - from->st_value), fromsec, tosym, tosec);
+ modname, fromsym,
+ (unsigned int)(faddr - (from ? from->st_value : 0)),
+ fromsec, tosym, tosec);
if (mismatch->mismatch == EXTABLE_TO_NON_TEXT) {
if (match(tosec, mismatch->bad_tosec))
--
2.39.2
next reply other threads:[~2024-02-15 14:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 14:13 Max Kellermann [this message]
2024-02-17 12:24 ` [PATCH] scripts/mod/modpost: fix null pointer dereference Masahiro Yamada
2024-02-17 15:02 ` Max Kellermann
2024-03-12 9:51 ` Max Kellermann
2024-03-18 17:31 ` Masahiro Yamada
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