Bug Summary

File:builds/wireshark/wireshark/epan/tvbuff_base64.c
Warning:line 249, column 9
Potential leak of memory pointed to by 'data'

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_base64.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-22/lib/clang/22 -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/lua5.5 -isystem /usr/include/libxml2 -D CARES_NO_DEPRECATED -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-22/lib/clang/22/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/16/../../../../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-nonliteral -std=gnu17 -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 -fdwarf2-cfi-asm -o /builds/wireshark/wireshark/sbout/2026-07-05-100322-3576-1 -x c /builds/wireshark/wireshark/epan/tvbuff_base64.c
1/* tvbuff_base64.c
2 * Base-64 tvbuff implementation (based on real tvb)
3 *
4 * Wireshark - Network traffic analyzer
5 * By Gerald Combs <[email protected]>
6 * Copyright 1998 Gerald Combs
7 *
8 * SPDX-License-Identifier: GPL-2.0-or-later
9 */
10
11#include "config.h"
12
13#include <glib.h>
14
15#include <epan/tvbuff.h>
16#include <wsutil/ws_padding_to.h>
17#include "proto.h"
18
19/* Copy of glib function modified for base64uri */
20
21static const unsigned char mime_base64uri_rank[256] = {
22 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
23 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
24 255,255,255,255,255,255,255,255,255,255,255, 255,255,63,255,255,
25 52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255, 0,255,255,
26 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
27 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,255,255,255,255, 63,
28 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
29 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,255,255,255,255,255,
30 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
31 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
32 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
33 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
34 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
35 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
36 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
37 255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
38};
39 /**
40 * Copy of glib function modified for base64uri
41 * g_base64uri_decode_step: (skip)
42 * @in: (array length=len) (element-type uint8_t): binary input data
43 * @len: max length of @in data to decode
44 * @out: (out caller-allocates) (array) (element-type uint8_t): output buffer
45 * @state: (inout): Saved state between steps, initialize to 0
46 * @save: (inout): Saved state between steps, initialize to 0
47 *
48 * Incrementally decode a sequence of binary data from its Base-64 stringified
49 * representation. By calling this function multiple times you can convert
50 * data in chunks to avoid having to have the full encoded data in memory.
51 *
52 * The output buffer must be large enough to fit all the data that will
53 * be written to it. Since base64 encodes 3 bytes in 4 chars you need
54 * at least: (@len / 4) * 3 + 3 bytes (+ 3 may be needed in case of non-zero
55 * state).
56 *
57 * Returns: The number of bytes of output that was written
58 *
59 * Since: 2.12
60 **/
61static size_t
62g_base64uri_decode_step(const char* in,
63 size_t len,
64 unsigned char* out,
65 int* state,
66 unsigned* save)
67{
68 const unsigned char* inptr;
69 unsigned char* outptr;
70 const unsigned char* inend;
71 unsigned char c, rank;
72 unsigned char last[2];
73 unsigned int v;
74 int i;
75
76 g_return_val_if_fail(in != NULL || len == 0, 0)do { if ((in != ((void*)0) || len == 0)) { } else { g_return_if_fail_warning
(((gchar*) 0), ((const char*) (__func__)), "in != NULL || len == 0"
); return (0); } } while (0);
9
←
Loop condition is false. Exiting loop
→
77 g_return_val_if_fail(out != NULL, 0)do { if ((out != ((void*)0))) { } else { g_return_if_fail_warning
(((gchar*) 0), ((const char*) (__func__)), "out != NULL"); return
(0); } } while (0);
10
←
Assuming 'out' is not equal to null
→
11
←
Taking true branch
→
12
←
Loop condition is false. Exiting loop
→
78 g_return_val_if_fail(state != NULL, 0)do { if ((state != ((void*)0))) { } else { g_return_if_fail_warning
(((gchar*) 0), ((const char*) (__func__)), "state != NULL");
return (0); } } while (0);
13
←
Taking true branch
→
14
←
Loop condition is false. Exiting loop
→
79 g_return_val_if_fail(save != NULL, 0)do { if ((save != ((void*)0))) { } else { g_return_if_fail_warning
(((gchar*) 0), ((const char*) (__func__)), "save != NULL"); return
(0); } } while (0);
15
←
Taking true branch
→
16
←
Loop condition is false. Exiting loop
→
80
81 if (len == 0)
17
←
Assuming 'len' is equal to 0
→
18
←
Taking true branch
→
82 return 0;
83
84 inend = (const unsigned char*)in + len;
85 outptr = out;
86
87 /* convert 4 base64 bytes to 3 normal bytes */
88 v = *save;
89 i = *state;
90
91 last[0] = last[1] = 0;
92
93 /* we use the sign in the state to determine if we got a padding character
94 in the previous sequence */
95 if (i < 0)
96 {
97 i = -i;
98 last[0] = '=';
99 }
100
101 inptr = (const unsigned char*)in;
102 while (inptr < inend)
103 {
104 c = *inptr++;
105 rank = mime_base64uri_rank[c];
106 if (rank != 0xff)
107 {
108 last[1] = last[0];
109 last[0] = c;
110 v = (v << 6) | rank;
111 i++;
112 if (i == 4)
113 {
114 *outptr++ = v >> 16;
115 if (last[1] != '=')
116 *outptr++ = v >> 8;
117 if (last[0] != '=')
118 *outptr++ = v;
119 i = 0;
120 }
121 }
122 }
123
124 *save = v;
125 *state = last[0] == '=' ? -i : i;
126
127 return outptr - out;
128}
129 /**
130 * Copy of glib function modified for base64uri
131 * g_base64uri_decode:
132 * @text: (not nullable): zero-terminated string with base64 text to decode
133 * @out_len: (out): The length of the decoded data is written here
134 *
135 * Decode a sequence of Base-64 encoded text into binary data. Note
136 * that the returned binary data is not necessarily zero-terminated,
137 * so it should not be used as a character string.
138 *
139 * Returns: (transfer full) (array length=out_len) (element-type uint8_t):
140 * newly allocated buffer containing the binary data
141 * that @text represents. The returned buffer must
142 * be freed with g_free().
143 *
144 * Since: 2.12
145 */
146static unsigned char*
147g_base64uri_decode(const char* text,
148 size_t* out_len)
149{
150 const char pad[4] = "===";
151 unsigned char* ret;
152 size_t input_length;
153 int state = 0;
154 unsigned save = 0;
155
156 g_return_val_if_fail(text != NULL, NULL)do { if ((text != ((void*)0))) { } else { g_return_if_fail_warning
(((gchar*) 0), ((const char*) (__func__)), "text != NULL"); return
(((void*)0)); } } while (0);
2
←
Assuming 'text' is not equal to null
→
3
←
Taking true branch
→
4
←
Loop condition is false. Exiting loop
→
157 g_return_val_if_fail(out_len != NULL, NULL)do { if ((out_len != ((void*)0))) { } else { g_return_if_fail_warning
(((gchar*) 0), ((const char*) (__func__)), "out_len != NULL"
); return (((void*)0)); } } while (0);
5
←
Taking true branch
→
6
←
Loop condition is false. Exiting loop
→
158
159 /* XXX - We could just pass in the length instead of calling strlen,
160 * which would allow using tvb_get_ptr. */
161 input_length = strlen(text);
162
163 /* In base64url padding is optional.
164 * https://www.rfc-editor.org/info/rfc4648/#section-5
165 * https://www.rfc-editor.org/info/rfc4648/#section-3.2
166 *
167 * https://www.rfc-editor.org/info/rfc4648/#section-4
168 */
169
170 /* We can use a smaller limit here, since we know the saved state is 0,
171 +1 used to avoid calling g_malloc0(0), and hence returning NULL */
172 /* Add an additional 1 to ensure there's enough space for the padding
173 * omitted case. (g_base64_decode_step mentions adding + 3 in the
174 * case of non-zero state, but that's only if the extra bytes added
175 * in are not all '='.) */
176 ret = (unsigned char * )g_malloc0((input_length / 4) * 3 + 2);
7
←
Memory is allocated
→
177
178 *out_len = g_base64uri_decode_step(text, input_length, ret, &state, &save);
8
←
Calling 'g_base64uri_decode_step'
→
19
←
Returning from 'g_base64uri_decode_step'
→
179
180 input_length = WS_PADDING_TO_4(input_length)((4U - ((input_length) % 4U)) % 4U);
181 if (input_length
19.1
'input_length' is 0
)
20
←
Taking false branch
→
182 *out_len += g_base64uri_decode_step(pad, input_length, &ret[*out_len], &state, &save);
183
184 return ret;
185}
186
187tvbuff_t *
188base64_to_tvb(tvbuff_t *parent, const char *base64)
189{
190 tvbuff_t *tvb;
191 uint8_t *data;
192 size_t len;
193
194 data = g_base64_decode(base64, &len);
195 tvb = tvb_new_child_real_data(parent, data, (unsigned)len, (unsigned)len);
196
197 tvb_set_free_cb(tvb, g_free);
198
199 return tvb;
200}
201
202tvbuff_t*
203base64_tvb_to_new_tvb(tvbuff_t* parent, unsigned offset, unsigned length)
204{
205 tvbuff_t* tvb;
206 uint8_t* data, *tmp;
207 size_t len;
208
209 /* g_base64_decode only requires NULL termination, not a valid UTF-8
210 * or ASCII string (it silently skips over invalid bytes, we don't
211 * check that either). So tvb_get_raw_bytes_as_string() would work,
212 * but we would need to check the length before allocating the buffer
213 * to avoid a memory leak (or push a CLEANUP function on exception).
214 *
215 * We could also implement our own function that took a length and
216 * didn't require NULL termination. We could also do that by simply
217 * calling g_base64_decode_step() directly.
218 */
219 tmp = tvb_get_string_enc(NULL((void*)0), parent, offset, length, ENC_ASCII0x00000000);
220 data = g_base64_decode((const char*)tmp, &len);
221 wmem_free(NULL((void*)0), tmp);
222
223 tvb = tvb_new_child_real_data(parent, data, (unsigned)len, (unsigned)len);
224
225 tvb_set_free_cb(tvb, g_free);
226
227 return tvb;
228}
229
230tvbuff_t*
231base64uri_tvb_to_new_tvb(tvbuff_t* parent, unsigned offset, unsigned length)
232{
233 tvbuff_t* tvb;
234 uint8_t* data, *tmp;
235 size_t len = 0;
236
237#if 0
238 size_t expected_output_len;
239 expected_output_length = (input_length / 4) * 3;
240 /* Note that input_length % 4 == 1 represents bad input and _should_
241 * never happen. Perhaps we should just consider it a failure. */
242 experted_output_length += ((input_length % 4) + 1) / 2;
243#endif
244
245 tmp = tvb_get_string_enc(NULL((void*)0), parent, offset, length, ENC_ASCII0x00000000);
246 data = g_base64uri_decode((const char*)tmp, &len);
1
Calling 'g_base64uri_decode'
→
21
←
Returned allocated memory
→
247 wmem_free(NULL((void*)0), tmp);
248
249 tvb = tvb_new_child_real_data(parent, data, (unsigned)len, (unsigned)len);
22
←
Potential leak of memory pointed to by 'data'
250
251 tvb_set_free_cb(tvb, g_free);
252
253 return tvb;
254}
255/*
256 * Editor modelines - https://www.wireshark.org/tools/modelines.html
257 *
258 * Local Variables:
259 * c-basic-offset: 2
260 * tab-width: 8
261 * indent-tabs-mode: nil
262 * End:
263 *
264 * ex: set shiftwidth=2 tabstop=8 expandtab:
265 * :indentSize=2:tabSize=8:noTabs=true:
266 */