From: lzhan011 <lzsx618@gmail.com>
To: nathan@kernel.org, nsc@kernel.org
Cc: rostedt@goodmis.org, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 8/9] sorttable: avoid pointer arithmetic overflow when locating sort_needed
Date: Mon, 5 Oct 2026 05:40:49 -0500 [thread overview]
Message-ID: <20261005104050.1786222-9-lzsx618@gmail.com> (raw)
In-Reply-To: <20261005104050.1786222-1-lzsx618@gmail.com>
From: lzhan011 <zhangleizhen645@gmail.com>
The location of the main_extable_sort_needed variable is computed as
(void *)ehdr + shdr_offset(sec) + sym_value(sym) - shdr_addr(sec)
which first adds the symbol's virtual address (e.g. 0xffffffff8...) to
the pointer and only then subtracts the section address. The
intermediate pointer overflows, which is undefined behaviour and is
reported by UBSan.
Subtract the section address from the symbol value first.
Fixes: a79f248b9b30 ("scripts: Add sortextable to sort the kernel's exception table.")
Assisted-by: Claude:claude-opus-5-5 UBSan
Signed-off-by: lzhan011 <zhangleizhen645@gmail.com>
---
scripts/sorttable.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/sorttable.c b/scripts/sorttable.c
index 88e49a5c4..0425e00c4 100644
--- a/scripts/sorttable.c
+++ b/scripts/sorttable.c
@@ -788,7 +788,7 @@ static int do_sort(Elf_Ehdr *ehdr,
sort_needed_sec = get_index(shdr_start, shentsize, sort_need_index);
sort_needed_loc = (void *)ehdr +
shdr_offset(sort_needed_sec) +
- sym_value(sort_needed_sym) - shdr_addr(sort_needed_sec);
+ (sym_value(sort_needed_sym) - shdr_addr(sort_needed_sec));
/* extable has been sorted, clear the flag */
elf_parser.w(0, sort_needed_loc);
--
2.34.1
next prev parent reply other threads:[~2026-10-05 10:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-05 10:40 [PATCH 0/9] kbuild: fix memory safety and UB bugs in host tools found by fuzzing lzhan011
2026-10-05 10:40 ` [PATCH 1/9] kconfig: fix NULL pointer dereference for defaults taken from choice members lzhan011
2026-10-08 16:04 ` Julian Braha
2026-10-05 10:40 ` [PATCH 2/9] genksyms: fix infinite loop on declarations with parameter lists lzhan011
2026-10-05 10:40 ` [PATCH 3/9] fixdep: fix out-of-bounds read on a comment ending with a backslash lzhan011
2026-10-05 10:40 ` [PATCH 4/9] kallsyms: do not call qsort() with a NULL table lzhan011
2026-10-05 10:40 ` [PATCH 5/9] modpost: fix stack out-of-bounds read for unterminated PNP ids lzhan011
2026-10-05 10:40 ` [PATCH 6/9] modpost: fix handling of short reads in read_text_file() lzhan011
2026-10-05 10:40 ` [PATCH 7/9] modpost: fix pointer arithmetic on NULL in parse_source_files() lzhan011
2026-10-05 10:40 ` lzhan011 [this message]
2026-10-05 10:40 ` [PATCH 9/9] tools/include: fix signed shift overflow in 32-bit unaligned accessors lzhan011
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