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Subject[PATCH 1/3] modpost: add array range check to sec_name()
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The section index is always positive, so the argunent, secindex, should
be unsigned.

Also, inserted the array range check.

If sym->st_shndx is a special section index (between SHN_LORESERVE and
SHN_HIRESERVE), there is no corresponding section header.

For example, if a symbol specifies an absolute value, sym->st_shndx is
SHN_ABS (=0xfff1).

The current users do not cause the out-of-range access of
info->sechddrs[], but it is better to avoid such a pitfall.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

scripts/mod/modpost.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 08411fff3e17..148b38699889 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -336,8 +336,16 @@ static const char *sech_name(const struct elf_info *info, Elf_Shdr *sechdr)
sechdr->sh_name);
}

-static const char *sec_name(const struct elf_info *info, int secindex)
+static const char *sec_name(const struct elf_info *info, unsigned int secindex)
{
+ /*
+ * If sym->st_shndx is a special section index, there is no
+ * corresponding section header.
+ * Return "" if the index is out of range of info->sechdrs[] array.
+ */
+ if (secindex >= info->num_sections)
+ return "";
+
return sech_name(info, &info->sechdrs[secindex]);
}

--
2.34.1
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