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[PATCH 5/6] target/s390x/arch_dump: Fixes for the name field in the PT_N
From: |
Thomas Huth |
Subject: |
[PATCH 5/6] target/s390x/arch_dump: Fixes for the name field in the PT_NOTE section |
Date: |
Wed, 3 Feb 2021 12:32:42 +0100 |
According to the "ELF-64 Object File Format" specification:
"The first word in the entry, namesz, identifies the length, in
bytes, of a name identifying the entry’s owner or originator. The name field
contains a null-terminated string, with padding as necessary to ensure 8-
byte alignment for the descriptor field. The length does not include the
terminating null or the padding."
So we should not include the terminating NUL in the length field here.
Also there is a compiler warning with GCC 9.3 when compiling with
the -fsanitize=thread compiler flag:
In function 'strncpy',
inlined from 's390x_write_elf64_notes' at ../target/s390x/arch_dump.c:219:9:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error:
'__builtin_strncpy' specified bound 8 equals destination size
[-Werror=stringop-truncation]
Since the name should always be NUL-terminated, we can simply decrease
the size of the strncpy by one here to silence this warning. And while
we're at it, also add an assert() to make sure that the provided names
always fit the size field (which is fine for the current callers, the
function is called once with "CORE" and once with "LINUX" as a name).
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
target/s390x/arch_dump.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/target/s390x/arch_dump.c b/target/s390x/arch_dump.c
index 50fa0ae4b6..20c3a09707 100644
--- a/target/s390x/arch_dump.c
+++ b/target/s390x/arch_dump.c
@@ -212,11 +212,13 @@ static int s390x_write_elf64_notes(const char *note_name,
int note_size;
int ret = -1;
+ assert(strlen(note_name) < sizeof(note.name));
+
for (nf = funcs; nf->note_contents_func; nf++) {
memset(¬e, 0, sizeof(note));
- note.hdr.n_namesz = cpu_to_be32(strlen(note_name) + 1);
+ note.hdr.n_namesz = cpu_to_be32(strlen(note_name));
note.hdr.n_descsz = cpu_to_be32(nf->contents_size);
- strncpy(note.name, note_name, sizeof(note.name));
+ strncpy(note.name, note_name, sizeof(note.name) - 1);
(*nf->note_contents_func)(¬e, cpu, id);
note_size = sizeof(note) - sizeof(note.contents) + nf->contents_size;
--
2.27.0
- Re: [PATCH 1/6] travis.yml: Move gprof/gcov test across to gitlab, (continued)
[PATCH 3/6] travis.yml: Move the --enable-modules test to the gitlab-CI, Thomas Huth, 2021/02/03
[PATCH 2/6] travis.yml: Move the -fsanitize=undefined test to the gitlab-CI, Thomas Huth, 2021/02/03
[PATCH 4/6] travis.yml: Remove the --enable-debug jobs, Thomas Huth, 2021/02/03
[PATCH 6/6] travis.yml: Move the -fsanitize=thread compile-testing to the gitlab-CI, Thomas Huth, 2021/02/03
[PATCH 5/6] target/s390x/arch_dump: Fixes for the name field in the PT_NOTE section,
Thomas Huth <=