### Bug Summary

File: | epan/tvbuff_brotli.c
Warning: | line 149, column 17 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_brotli.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/2025-10-14-100335-3623-1 -x c /builds/wireshark/wireshark/epan/tvbuff_brotli.c

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1 | /* tvbuff_brotli.c
2 | *
3 | * Wireshark - Network traffic analyzer
4 | * By Gerald Combs <gerald@wireshark.org>
5 | * Copyright 1998 Gerald Combs
6 | *
7 | * SPDX-License-Identifier: GPL-2.0-or-later
8 | */
9 |
10 | #include <config.h>
11 |
12 | #include <glib.h>
13 |
14 | #include <string.h>
15 |
16 | #ifdef HAVE_BROTLI1
17 | #include <brotli/decode.h>
18 | #endif
19 |
20 | #include "tvbuff.h"
21 |
22 | #ifdef HAVE_BROTLI1
23 |
24 | /*
25 | * 512KiB is the buffer size used by the brotli tool, so we
26 | * use that too.
27 | */
28 | #define TVB_BROTLI_BUFSIZ(1 << 19) (1 << 19)
29 |
30 | static void*
31 | brotli_g_malloc_wrapper(void *opaque _U___attribute__((unused)), size_t size)
32 | {
33 | return g_malloc(size);
34 | }
35 |
36 | static void
37 | brotli_g_free_wrapper(void *opaque _U___attribute__((unused)), void *address)
38 | {
39 | g_free(address);
40 | }
41 |
42 | /*
43 | * Uncompresses a brotli compressed packet inside a message of tvb at offset with
44 | * length comprlen. Returns an uncompressed tvbuffer if uncompression
45 | * succeeded or NULL if uncompression failed.
46 | */
47 |
48 | tvbuff_t *
49 | tvb_uncompress_brotli(tvbuff_t *tvb, const int offset, int comprlen)
50 | {
51 | uint8_t *compr;
52 | uint8_t *uncompr = NULL((void*)0);
53 | tvbuff_t *uncompr_tvb;
54 | BrotliDecoderState *decoder;
55 | uint8_t *strmbuf;
56 | const size_t bufsiz = TVB_BROTLI_BUFSIZ(1 << 19);
57 | size_t available_in;
58 | const uint8_t *next_in;
59 | size_t available_out;
60 | uint8_t *next_out;
61 | size_t total_out;
62 | unsigned needs_more_output;
63 | unsigned finished;
64 |
65 | if (tvb == NULL((void*)0) || comprlen <= 0) {
2 | ← | Assuming 'tvb' is not equal to NULL | →
3 | ← | Assuming 'comprlen' is > 0 | →
4 | ← | Taking false branch | →
66 | return NULL((void*)0);
67 | }
68 |
69 | compr = (uint8_t *)tvb_memdup(NULL((void*)0), tvb, offset, comprlen);
70 | if (compr == NULL((void*)0)) {
5 | ← | Assuming 'compr' is not equal to NULL | →
6 | ← | Taking false branch | →
71 | return NULL((void*)0);
72 | }
73 |
74 | decoder = BrotliDecoderCreateInstance(
75 | &brotli_g_malloc_wrapper /*alloc_func*/,
76 | &brotli_g_free_wrapper /*free_func*/,
77 | NULL((void*)0) /*opaque*/);
78 | if (decoder == NULL((void*)0)) {
7 | ← | Assuming 'decoder' is not equal to NULL | →
8 | ← | Taking false branch | →
79 | wmem_free(NULL((void*)0), compr);
80 | return NULL((void*)0);
81 | }
82 | strmbuf = (uint8_t *)g_malloc(bufsiz);
83 |
84 | available_in = comprlen;
85 | next_in = compr;
86 | total_out = 0;
87 | needs_more_output = 0;
88 | finished = 0;
89 | while (available_in
8.1 | 'available_in' is > 0
> 0 || needs_more_output) {
16 | ← | Assuming 'available_in' is <= 0 | →
17 | ← | Loop condition is false. Execution continues on line 137 | →
90 | needs_more_output = 0;
91 | available_out = bufsiz;
92 | next_out = strmbuf;
93 |
94 | BrotliDecoderResult result = BrotliDecoderDecompressStream(
95 | decoder, &available_in, &next_in, &available_out, &next_out, &total_out);
96 | switch (result) {
9 | ← | Control jumps to 'case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT:' at line 106 | →
97 | case BROTLI_DECODER_RESULT_SUCCESS:
98 | if (available_in > 0) {
99 | goto cleanup;
100 | }
101 | finished = 1;
102 | break;
103 | case BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT:
104 | needs_more_output = 1;
105 | break;
106 | case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT:
107 | /*
108 | * It's possible that not enough frames were captured
109 | * to decompress this fully, so return what we've done
110 | * so far, if any.
111 | */
112 | break;
113 | case BROTLI_DECODER_RESULT_ERROR:
114 | default:
115 | goto cleanup;
116 | }
117 |
118 | /*
119 | * Check if decompressed size is too large.
120 | */
121 | if (total_out > INT_MAX2147483647) {
10 | ← | Execution continues on line 121 | →
11 | ← | Assuming 'total_out' is <= INT_MAX | →
12 | ← | Taking false branch | →
122 | goto cleanup;
123 | }
124 |
125 | /*
126 | * BrotliDecoderDecompressStream sets available_out to the number of bytes
127 | * left unused from the buffer. But we are interested in the bytes it wrote
128 | * to the buffer in this pass, so we calculate pass_out.
129 | */
130 | size_t pass_out = bufsiz - available_out;
131 | if (pass_out > 0) {
13 | ← | Assuming 'pass_out' is > 0 | →
14 | ← | Taking true branch | →
132 | uncompr = (uint8_t *)g_realloc(uncompr, total_out);
15 | ← | Memory is allocated | →
133 | memcpy(uncompr + (total_out - pass_out), strmbuf, pass_out);
134 | }
135 | }
136 |
137 | if (uncompr
17.1 | 'uncompr' is not equal to NULL
== NULL((void*)0)) {
18 | ← | Taking false branch | →
138 | /*
139 | * This is for the case when the validly decompressed
140 | * length is 0.
141 | */
142 | if (finished) {
143 | uncompr = (uint8_t *)g_strdup("")g_strdup_inline ("");
144 | } else {
145 | goto cleanup;
146 | }
147 | }
148 |
149 | uncompr_tvb = tvb_new_real_data((uint8_t *)uncompr, (unsigned)total_out, (int)total_out);
19 | ← | Potential leak of memory pointed to by 'uncompr'
150 | tvb_set_free_cb(uncompr_tvb, g_free);
151 |
152 | g_free(strmbuf);
153 | wmem_free(NULL((void*)0), compr);
154 | BrotliDecoderDestroyInstance(decoder);
155 | return uncompr_tvb;
156 |
157 | cleanup:
158 | g_free(strmbuf);
159 | g_free(uncompr);
160 | wmem_free(NULL((void*)0), compr);
161 | BrotliDecoderDestroyInstance(decoder);
162 | return NULL((void*)0);
163 | }
164 | #else
165 | tvbuff_t *
166 | tvb_uncompress_brotli(tvbuff_t *tvb _U___attribute__((unused)), const int offset _U___attribute__((unused)), int comprlen _U___attribute__((unused)))
167 | {
168 | return NULL((void*)0);
169 | }
170 | #endif
171 |
172 | tvbuff_t *
173 | tvb_child_uncompress_brotli(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int comprlen)
174 | {
175 | tvbuff_t *new_tvb = tvb_uncompress_brotli(tvb, offset, comprlen);
1 | Calling 'tvb_uncompress_brotli' | →
176 | if (new_tvb)
177 | tvb_set_child_real_data_tvbuff(parent, new_tvb);
178 | return new_tvb;
179 | }
180 |
181 | /*
182 | * Editor modelines - https://www.wireshark.org/tools/modelines.html
183 | *
184 | * Local variables:
185 | * c-basic-offset: 4
186 | * tab-width: 8
187 | * indent-tabs-mode: nil
188 | * End:
189 | *
190 | * vi: set shiftwidth=4 tabstop=8 expandtab:
191 | * :indentSize=4:tabSize=8:noTabs=true:
192 | */