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-rw-r--r--meta-oe/recipes-kernel/libbpf/files/0001-libbpf-check-for-empty-BTF-data-section-in-btf_parse.patch43
-rw-r--r--meta-oe/recipes-kernel/libbpf/files/CVE-2025-29481.patch102
2 files changed, 145 insertions, 0 deletions
diff --git a/meta-oe/recipes-kernel/libbpf/files/0001-libbpf-check-for-empty-BTF-data-section-in-btf_parse.patch b/meta-oe/recipes-kernel/libbpf/files/0001-libbpf-check-for-empty-BTF-data-section-in-btf_parse.patch
new file mode 100644
index 0000000000..873995b644
--- /dev/null
+++ b/meta-oe/recipes-kernel/libbpf/files/0001-libbpf-check-for-empty-BTF-data-section-in-btf_parse.patch
@@ -0,0 +1,43 @@
1From ff2eb6e134ebfc225b97b46182af3cc58ed481f6 Mon Sep 17 00:00:00 2001
2From: Changqing Li <changqing.li@windriver.com>
3Date: Thu, 10 Apr 2025 11:50:04 +0800
4Subject: [PATCH] libbpf: check for empty BTF data section in btf_parse_elf
5
6A valid ELF file may contain a SHT_NOBITS .BTF section. This case is
7not handled correctly in btf_parse_elf, which leads to a segfault.
8
9Add a null check for a buffer returned by elf_getdata() before
10proceeding with its processing.
11
12Bug report: https://github.com/libbpf/libbpf/issues/894
13
14Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
15Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
16
17Upstream-Status: Backport [https://github.com/kernel-patches/bpf-rc/commit/b02b669fd9398d246c8c9ae901c0d8f5bb36a588]
18
19Signed-off-by: Changqing Li <changqing.li@windriver.com>
20---
21 btf.c | 6 ++++++
22 1 file changed, 6 insertions(+)
23
24diff --git a/btf.c b/btf.c
25index e9673c0e..21d38dcf 100644
26--- a/btf.c
27+++ b/btf.c
28@@ -1199,6 +1199,12 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf,
29 goto done;
30 }
31
32+ if (!secs.btf_data->d_buf) {
33+ pr_warn("BTF data is empty in %s\n", path);
34+ err = -ENODATA;
35+ goto done;
36+ }
37+
38 if (secs.btf_base_data) {
39 dist_base_btf = btf_new(secs.btf_base_data->d_buf, secs.btf_base_data->d_size,
40 NULL);
41--
422.34.1
43
diff --git a/meta-oe/recipes-kernel/libbpf/files/CVE-2025-29481.patch b/meta-oe/recipes-kernel/libbpf/files/CVE-2025-29481.patch
new file mode 100644
index 0000000000..ebfcb94a2f
--- /dev/null
+++ b/meta-oe/recipes-kernel/libbpf/files/CVE-2025-29481.patch
@@ -0,0 +1,102 @@
1From 806b4e0a9f658d831119cece11a082ba1578b800 Mon Sep 17 00:00:00 2001
2From: Viktor Malik <vmalik@redhat.com>
3Date: Tue, 15 Apr 2025 17:50:14 +0200
4Subject: [PATCH] libbpf: Fix buffer overflow in bpf_object__init_prog
5
6As shown in [1], it is possible to corrupt a BPF ELF file such that
7arbitrary BPF instructions are loaded by libbpf. This can be done by
8setting a symbol (BPF program) section offset to a large (unsigned)
9number such that <section start + symbol offset> overflows and points
10before the section data in the memory.
11
12Consider the situation below where:
13- prog_start = sec_start + symbol_offset <-- size_t overflow here
14- prog_end = prog_start + prog_size
15
16 prog_start sec_start prog_end sec_end
17 | | | |
18 v v v v
19 .....................|################################|............
20
21The report in [1] also provides a corrupted BPF ELF which can be used as
22a reproducer:
23
24 $ readelf -S crash
25 Section Headers:
26 [Nr] Name Type Address Offset
27 Size EntSize Flags Link Info Align
28 ...
29 [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040
30 0000000000000068 0000000000000000 AX 0 0 8
31
32 $ readelf -s crash
33 Symbol table '.symtab' contains 8 entries:
34 Num: Value Size Type Bind Vis Ndx Name
35 ...
36 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp
37
38Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
39point before the actual memory where section 2 is allocated.
40
41This is also reported by AddressSanitizer:
42
43 =================================================================
44 ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
45 READ of size 104 at 0x7c7302fe0000 thread T0
46 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
47 #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
48 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
49 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
50 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
51 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
52 #6 0x000000400c16 in main /poc/poc.c:8
53 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
54 #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
55 #9 0x000000400b34 in _start (/poc/poc+0x400b34)
56
57 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
58 allocated by thread T0 here:
59 #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
60 #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
61 #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
62 #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740
63
64The problem here is that currently, libbpf only checks that the program
65end is within the section bounds. There used to be a check
66`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
67removed by commit 6245947c1b3c ("libbpf: Allow gaps in BPF program
68sections to support overriden weak functions").
69
70Add a check for detecting the overflow of `sec_off + prog_sz` to
71bpf_object__init_prog to fix this issue.
72
73[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
74
75Fixes: 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
76Reported-by: lmarch2 <2524158037@qq.com>
77Signed-off-by: Viktor Malik <vmalik@redhat.com>
78Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
79Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
80Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
81Link: https://lore.kernel.org/bpf/20250415155014.397603-1-vmalik@redhat.com
82
83CVE: CVE-2025-29481
84Upstream-Status: Backport [https://github.com/libbpf/libbpf/commit/806b4e0a9f658d831119cece11a082ba1578b800]
85Signed-off-by: Peter Marko <peter.marko@siemens.com>
86---
87 src/libbpf.c | 2 +-
88 1 file changed, 1 insertion(+), 1 deletion(-)
89
90diff --git a/src/libbpf.c b/src/libbpf.c
91index b2591f5..56250b5 100644
92--- a/src/libbpf.c
93+++ b/src/libbpf.c
94@@ -889,7 +889,7 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data,
95 return -LIBBPF_ERRNO__FORMAT;
96 }
97
98- if (sec_off + prog_sz > sec_sz) {
99+ if (sec_off + prog_sz > sec_sz || sec_off + prog_sz < sec_off) {
100 pr_warn("sec '%s': program at offset %zu crosses section boundary\n",
101 sec_name, sec_off);
102 return -LIBBPF_ERRNO__FORMAT;