### Bug Summary

File: | epan/tvbuff_zstd.c
Warning: | line 87, column 21 Potential leak of memory pointed to by 'uncompr'

### Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name tvbuff_zstd.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -fno-delete-null-pointer-checks -mframe-pointer=all -relaxed-aliasing -fmath-errno -ffp-contract=on -fno-rounding-math -ffloat16-excess-precision=fast -fbfloat16-excess-precision=fast -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/builds/wireshark/wireshark/build -fcoverage-compilation-dir=/builds/wireshark/wireshark/build -resource-dir /usr/lib/llvm-21/lib/clang/21 -isystem /usr/include/glib-2.0 -isystem /usr/lib/x86_64-linux-gnu/glib-2.0/include -isystem /builds/wireshark/wireshark/epan -isystem /builds/wireshark/wireshark/build/epan -isystem /usr/include/mit-krb5 -isystem /usr/include/libxml2 -isystem /usr/include/lua5.4 -D G_DISABLE_DEPRECATED -D G_DISABLE_SINGLE_INCLUDES -D WS_BUILD_DLL -D WS_DEBUG -D WS_DEBUG_UTF_8 -D epan_EXPORTS -I /builds/wireshark/wireshark/build -I /builds/wireshark/wireshark -I /builds/wireshark/wireshark/include -I /builds/wireshark/wireshark/wiretap -D _GLIBCXX_ASSERTIONS -internal-isystem /usr/lib/llvm-21/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/builds/wireshark/wireshark/= -fmacro-prefix-map=/builds/wireshark/wireshark/build/= -fmacro-prefix-map=../= -Wno-format-truncation -Wno-format-nonliteral -Wno-pointer-sign -std=gnu11 -ferror-limit 19 -fvisibility=hidden -fwrapv -fwrapv-pointer -fstrict-flex-arrays=3 -stack-protector 2 -fstack-clash-protection -fcf-protection=full -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fexceptions -fcolor-diagnostics -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /builds/wireshark/wireshark/sbout/2025-10-31-100325-3623-1 -x c /builds/wireshark/wireshark/epan/tvbuff_zstd.c

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1 | /* tvbuff_zstd.c
2 | * Copyright 2022, Kevin Albertson <kevin.eric.albertson [AT] gmail.com>
3 | *
4 | * Wireshark - Network traffic analyzer
5 | * By Gerald Combs <gerald@wireshark.org>
6 | * Copyright 1998 Gerald Combs
7 | *
8 | * SPDX-License-Identifier: GPL-2.0-or-later
9 | */
10 |
11 | /*
12 | * Decompress ZSTD: http://facebook.github.io/zstd/
13 | */
14 |
15 | #include "config.h"
16 |
17 | #ifdef HAVE_ZSTD1
18 | #include <zstd.h>
19 | #endif
20 |
21 | #include "proto.h" // DISSECTOR_ASSERT_HINT
22 | #include "tvbuff.h"
23 |
24 | #include "tvbuff-int.h" // tvb_add_to_chain
25 |
26 | #define MAX_LOOP_ITERATIONS100 100
27 |
28 | tvbuff_t *tvb_uncompress_zstd(tvbuff_t *tvb, const int offset, int comprlen)
29 | {
30 | #ifndef HAVE_ZSTD1
31 | // Cast to void to silence unused warnings.
32 | (void)tvb;
33 | (void)offset;
34 | (void)comprlen;
35 | return NULL((void*)0);
36 | #else
37 | ZSTD_inBuffer input = {tvb_memdup(NULL((void*)0), tvb, offset, comprlen), comprlen, 0};
38 | ZSTD_DStream *zds = ZSTD_createDStream();
39 | size_t rc = 0;
40 | uint8_t *uncompr = NULL((void*)0);
41 | size_t uncompr_len = 0;
42 | bool_Bool ok = false0;
43 | int count = 0;
44 |
45 | // ZSTD does not consume the last byte of the frame until it has flushed all of the decompressed data of the frame.
46 | // Therefore, loop while there is more input.
47 | ZSTD_outBuffer output = {g_malloc(ZSTD_DStreamOutSize()), ZSTD_DStreamOutSize(), 0};
48 | while (input.pos < input.size && count < MAX_LOOP_ITERATIONS100)
2 | ← | Assuming field 'pos' is < field 'size' | →
3 | ← | Loop condition is true. Entering loop body | →
12 | ← | Assuming field 'pos' is >= field 'size' | →
49 | {
50 | rc = ZSTD_decompressStream(zds, &output, &input);
51 | if (ZSTD_isError(rc))
4 | ← | Assuming the condition is false | →
5 | ← | Taking false branch | →
52 | {
53 | goto end;
54 | }
55 |
56 | if (output.pos > 0)
6 | ← | Assuming field 'pos' is > 0 | →
7 | ← | Taking true branch | →
57 | {
58 | if (!uncompr
7.1 | 'uncompr' is null
)
59 | {
60 | DISSECTOR_ASSERT (uncompr_len == 0)((void) ((uncompr_len == 0) ? (void)0 : (proto_report_dissector_bug ("%s:%u: failed assertion \"%s\"", "epan/tvbuff_zstd.c", 60, "uncompr_len == 0" ))));
8 | ← | Taking true branch | →
9 | ← | '?' condition is true | →
61 | uncompr = g_malloc(output.pos);
10 | ← | Memory is allocated | →
62 | } else {
63 | uncompr = g_realloc(uncompr, uncompr_len + output.pos);
64 | }
65 | memcpy (uncompr + uncompr_len, output.dst, output.pos);
66 | uncompr_len += output.pos;
67 | // Reset the output buffer.
68 | output.pos = 0;
69 | }
70 | count++;
71 | DISSECTOR_ASSERT_HINT(count < MAX_LOOP_ITERATIONS, "MAX_LOOP_ITERATIONS exceeded")((void) ((count < 100) ? (void)0 : (proto_report_dissector_bug ("%s:%u: failed assertion \"%s\" (%s)", "epan/tvbuff_zstd.c", 71, "count < 100", "MAX_LOOP_ITERATIONS exceeded"))));
11 | ← | '?' condition is true | →
72 | }
73 | if (rc > 0)
13 | ← | Assuming 'rc' is <= 0 | →
14 | ← | Taking false branch | →
74 | {
75 | // There is extra data that was not decompressed.
76 | goto end;
77 | }
78 |
79 | ok = true1;
80 | end:
81 | g_free((void *)output.dst);
82 | wmem_free(NULL((void*)0), (void *)input.src);
83 | ZSTD_freeDStream(zds);
84 | if (ok
14.1 | 'ok' is true
)
15 | ← | Taking true branch | →
85 | {
86 | tvbuff_t *uncompr_tvb;
87 | uncompr_tvb = tvb_new_real_data (uncompr, (unsigned)uncompr_len, (unsigned)uncompr_len);
16 | ← | Potential leak of memory pointed to by 'uncompr'
88 | tvb_set_free_cb (uncompr_tvb, g_free);
89 | return uncompr_tvb;
90 | }
91 |
92 | if (uncompr)
93 | {
94 | g_free (uncompr);
95 | }
96 |
97 | return NULL((void*)0);
98 | #endif /* HAVE_ZSTD */
99 | }
100 |
101 | tvbuff_t *tvb_child_uncompress_zstd(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int comprlen)
102 | {
103 | tvbuff_t *uncompressed = tvb_uncompress_zstd(tvb, offset, comprlen);
1 | Calling 'tvb_uncompress_zstd' | →
104 | if (!uncompressed)
105 | {
106 | return uncompressed;
107 | }
108 | tvb_add_to_chain(parent, uncompressed);
109 | return uncompressed;
110 | }