Re: [ovs-dev] [PATCH] ofp-actions: Fix use-after-free while decoding RAW_ENCAP.
On 2/17/21 2:47 AM, William Tu wrote:
> On Tue, Feb 16, 2021 at 2:27 PM Ilya Maximets wrote:
>>
>> While decoding RAW_ENCAP action, decode_ed_prop() might re-allocate
>> ofpbuf if there is no enough space left. However, function
>> 'decode_NXAST_RAW_ENCAP' continues to use old pointer to 'encap'
>> structure leading to write-after-free and incorrect decoding.
>>
>> ==3549105==ERROR: AddressSanitizer: heap-use-after-free on address
>> 0x6060011a at pc 0x005f6cc6 bp 0x7ffc3a2d4410 sp 0x7ffc3a2d4408
>> WRITE of size 2 at 0x6060011a thread T0
>> #0 0x5f6cc5 in decode_NXAST_RAW_ENCAP lib/ofp-actions.c:4461:20
>> #1 0x5f0551 in ofpact_decode ./lib/ofp-actions.inc2:4777:16
>> #2 0x5ed17c in ofpacts_decode lib/ofp-actions.c:7752:21
>> #3 0x5eba9a in ofpacts_pull_openflow_actions__ lib/ofp-actions.c:7791:13
>> #4 0x5eb9fc in ofpacts_pull_openflow_actions lib/ofp-actions.c:7835:12
>> #5 0x64bb8b in ofputil_decode_packet_out lib/ofp-packet.c:1113:17
>> #6 0x65b6f4 in ofp_print_packet_out lib/ofp-print.c:148:13
>> #7 0x659e3f in ofp_to_string__ lib/ofp-print.c:1029:16
>> #8 0x659b24 in ofp_to_string lib/ofp-print.c:1244:21
>> #9 0x65a28c in ofp_print lib/ofp-print.c:1288:28
>> #10 0x540d11 in ofctl_ofp_parse utilities/ovs-ofctl.c:2814:9
>> #11 0x564228 in ovs_cmdl_run_command__ lib/command-line.c:247:17
>> #12 0x56408a in ovs_cmdl_run_command lib/command-line.c:278:5
>> #13 0x5391ae in main utilities/ovs-ofctl.c:179:9
>> #14 0x7f6911ce9081 in __libc_start_main (/lib64/libc.so.6+0x27081)
>> #15 0x461fed in _start (utilities/ovs-ofctl+0x461fed)
>>
>> Fix that by getting a new pointer before using.
>>
>> Credit to OSS-Fuzz.
>>
>> Fuzzer regression test will fail only with AddressSanitizer enabled.
>>
>> Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27851
>> Fixes: f839892a206a ("OF support and translation of generic encap and decap")
>> Signed-off-by: Ilya Maximets
>
>
> LGTM.
> Acked-by: William Tu
>
Thanks!
Applied to master and backported down to 2.11.
Patch doesn't apply cleanly to older branches, so I didn't backport it there.
Best regards, Ilya Maximets.
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Re: [ovs-dev] [PATCH] ofp-actions: Fix use-after-free while decoding RAW_ENCAP.
On Tue, Feb 16, 2021 at 2:27 PM Ilya Maximets wrote:
>
> While decoding RAW_ENCAP action, decode_ed_prop() might re-allocate
> ofpbuf if there is no enough space left. However, function
> 'decode_NXAST_RAW_ENCAP' continues to use old pointer to 'encap'
> structure leading to write-after-free and incorrect decoding.
>
> ==3549105==ERROR: AddressSanitizer: heap-use-after-free on address
> 0x6060011a at pc 0x005f6cc6 bp 0x7ffc3a2d4410 sp 0x7ffc3a2d4408
> WRITE of size 2 at 0x6060011a thread T0
> #0 0x5f6cc5 in decode_NXAST_RAW_ENCAP lib/ofp-actions.c:4461:20
> #1 0x5f0551 in ofpact_decode ./lib/ofp-actions.inc2:4777:16
> #2 0x5ed17c in ofpacts_decode lib/ofp-actions.c:7752:21
> #3 0x5eba9a in ofpacts_pull_openflow_actions__ lib/ofp-actions.c:7791:13
> #4 0x5eb9fc in ofpacts_pull_openflow_actions lib/ofp-actions.c:7835:12
> #5 0x64bb8b in ofputil_decode_packet_out lib/ofp-packet.c:1113:17
> #6 0x65b6f4 in ofp_print_packet_out lib/ofp-print.c:148:13
> #7 0x659e3f in ofp_to_string__ lib/ofp-print.c:1029:16
> #8 0x659b24 in ofp_to_string lib/ofp-print.c:1244:21
> #9 0x65a28c in ofp_print lib/ofp-print.c:1288:28
> #10 0x540d11 in ofctl_ofp_parse utilities/ovs-ofctl.c:2814:9
> #11 0x564228 in ovs_cmdl_run_command__ lib/command-line.c:247:17
> #12 0x56408a in ovs_cmdl_run_command lib/command-line.c:278:5
> #13 0x5391ae in main utilities/ovs-ofctl.c:179:9
> #14 0x7f6911ce9081 in __libc_start_main (/lib64/libc.so.6+0x27081)
> #15 0x461fed in _start (utilities/ovs-ofctl+0x461fed)
>
> Fix that by getting a new pointer before using.
>
> Credit to OSS-Fuzz.
>
> Fuzzer regression test will fail only with AddressSanitizer enabled.
>
> Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27851
> Fixes: f839892a206a ("OF support and translation of generic encap and decap")
> Signed-off-by: Ilya Maximets
LGTM.
Acked-by: William Tu
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[ovs-dev] [PATCH] ofp-actions: Fix use-after-free while decoding RAW_ENCAP.
While decoding RAW_ENCAP action, decode_ed_prop() might re-allocate
ofpbuf if there is no enough space left. However, function
'decode_NXAST_RAW_ENCAP' continues to use old pointer to 'encap'
structure leading to write-after-free and incorrect decoding.
==3549105==ERROR: AddressSanitizer: heap-use-after-free on address
0x6060011a at pc 0x005f6cc6 bp 0x7ffc3a2d4410 sp 0x7ffc3a2d4408
WRITE of size 2 at 0x6060011a thread T0
#0 0x5f6cc5 in decode_NXAST_RAW_ENCAP lib/ofp-actions.c:4461:20
#1 0x5f0551 in ofpact_decode ./lib/ofp-actions.inc2:4777:16
#2 0x5ed17c in ofpacts_decode lib/ofp-actions.c:7752:21
#3 0x5eba9a in ofpacts_pull_openflow_actions__ lib/ofp-actions.c:7791:13
#4 0x5eb9fc in ofpacts_pull_openflow_actions lib/ofp-actions.c:7835:12
#5 0x64bb8b in ofputil_decode_packet_out lib/ofp-packet.c:1113:17
#6 0x65b6f4 in ofp_print_packet_out lib/ofp-print.c:148:13
#7 0x659e3f in ofp_to_string__ lib/ofp-print.c:1029:16
#8 0x659b24 in ofp_to_string lib/ofp-print.c:1244:21
#9 0x65a28c in ofp_print lib/ofp-print.c:1288:28
#10 0x540d11 in ofctl_ofp_parse utilities/ovs-ofctl.c:2814:9
#11 0x564228 in ovs_cmdl_run_command__ lib/command-line.c:247:17
#12 0x56408a in ovs_cmdl_run_command lib/command-line.c:278:5
#13 0x5391ae in main utilities/ovs-ofctl.c:179:9
#14 0x7f6911ce9081 in __libc_start_main (/lib64/libc.so.6+0x27081)
#15 0x461fed in _start (utilities/ovs-ofctl+0x461fed)
Fix that by getting a new pointer before using.
Credit to OSS-Fuzz.
Fuzzer regression test will fail only with AddressSanitizer enabled.
Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27851
Fixes: f839892a206a ("OF support and translation of generic encap and decap")
Signed-off-by: Ilya Maximets
---
lib/ofp-actions.c | 2 ++
tests/automake.mk | 3 ++-
tests/fuzz-regression-list.at | 1 +
.../ofp_print_fuzzer-6540965472632832 | Bin 0 -> 72 bytes
4 files changed, 5 insertions(+), 1 deletion(-)
create mode 100644 tests/fuzz-regression/ofp_print_fuzzer-6540965472632832
diff --git a/lib/ofp-actions.c b/lib/ofp-actions.c
index e2e829772..0342a228b 100644
--- a/lib/ofp-actions.c
+++ b/lib/ofp-actions.c
@@ -4431,6 +4431,7 @@ decode_NXAST_RAW_ENCAP(const struct nx_action_encap *nae,
{
struct ofpact_encap *encap;
const struct ofp_ed_prop_header *ofp_prop;
+const size_t encap_ofs = out->size;
size_t props_len;
uint16_t n_props = 0;
int err;
@@ -4458,6 +4459,7 @@ decode_NXAST_RAW_ENCAP(const struct nx_action_encap *nae,
}
n_props++;
}
+encap = ofpbuf_at_assert(out, encap_ofs, sizeof *encap);
encap->n_props = n_props;
out->header = >ofpact;
ofpact_finish_ENCAP(out, );
diff --git a/tests/automake.mk b/tests/automake.mk
index dfec2ea10..44a65849c 100644
--- a/tests/automake.mk
+++ b/tests/automake.mk
@@ -134,7 +134,8 @@ FUZZ_REGRESSION_TESTS = \
tests/fuzz-regression/ofp_print_fuzzer-5722747668791296 \
tests/fuzz-regression/ofp_print_fuzzer-6285128790704128 \
tests/fuzz-regression/ofp_print_fuzzer-6470117922701312 \
- tests/fuzz-regression/ofp_print_fuzzer-6502620041576448
+ tests/fuzz-regression/ofp_print_fuzzer-6502620041576448 \
+ tests/fuzz-regression/ofp_print_fuzzer-6540965472632832
$(srcdir)/tests/fuzz-regression-list.at: tests/automake.mk
$(AM_V_GEN)for name in $(FUZZ_REGRESSION_TESTS); do \
basename=`echo $$name | sed 's,^.*/,,'`; \
diff --git a/tests/fuzz-regression-list.at b/tests/fuzz-regression-list.at
index e3173fb88..2347c690e 100644
--- a/tests/fuzz-regression-list.at
+++ b/tests/fuzz-regression-list.at
@@ -21,3 +21,4 @@ TEST_FUZZ_REGRESSION([ofp_print_fuzzer-5722747668791296])
TEST_FUZZ_REGRESSION([ofp_print_fuzzer-6285128790704128])
TEST_FUZZ_REGRESSION([ofp_print_fuzzer-6470117922701312])
TEST_FUZZ_REGRESSION([ofp_print_fuzzer-6502620041576448])
+TEST_FUZZ_REGRESSION([ofp_print_fuzzer-6540965472632832])
diff --git a/tests/fuzz-regression/ofp_print_fuzzer-6540965472632832
b/tests/fuzz-regression/ofp_print_fuzzer-6540965472632832
new file mode 100644
index
..2977ee312bd64025f458e0f4bd6bcf6ecdba9b29
GIT binary patch
literal 72
zcmX|$F$w@648$Vn=https://mail.openvswitch.org/mailman/listinfo/ovs-dev
