Bug Summary

File:src/lib/libelf/libelf_ehdr.c
Warning:line 76, column 7
Although the value stored to 'shtype' is used in the enclosing expression, the value is never actually read from 'shtype'

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name libelf_ehdr.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -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 1 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/lib/libelf/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/lib/libelf -D PIC -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/lib/libelf/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/lib/libelf/libelf_ehdr.c
1/*-
2 * Copyright (c) 2006,2008 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <assert.h>
28#include <gelf.h>
29#include <libelf.h>
30#include <stdlib.h>
31
32#include "_libelf.h"
33
34ELFTC_VCSID("$Id: libelf_ehdr.c,v 1.3 2020/05/18 06:46:23 jsg Exp $")__asm__(".ident\t\"" "$Id: libelf_ehdr.c,v 1.3 2020/05/18 06:46:23 jsg Exp $"
"\"");
35
36/*
37 * Retrieve counts for sections, phdrs and the section string table index
38 * from section header #0 of the ELF object.
39 */
40static int
41_libelf_load_extended(Elf *e, int ec, uint64_t shoff, uint16_t phnum,
42 uint16_t strndx)
43{
44 size_t fsz;
45 Elf_Scn *scn;
46 uint32_t shtype;
47 _libelf_translator_function *xlator;
48
49 assert(STAILQ_EMPTY(&e->e_u.e_elf.e_scn))(((((&e->e_u.e_elf.e_scn)->stqh_first) == ((void *)
0))) ? (void)0 : __assert2("/usr/src/lib/libelf/libelf_ehdr.c"
, 49, __func__, "STAILQ_EMPTY(&e->e_u.e_elf.e_scn)"));
50
51 fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, 1);
52 assert(fsz > 0)((fsz > 0) ? (void)0 : __assert2("/usr/src/lib/libelf/libelf_ehdr.c"
, 52, __func__, "fsz > 0"));
53
54 if (shoff + fsz < shoff) { /* Numeric overflow. */
55 LIBELF_SET_ERROR(HEADER, 0)do { (_libelf.libelf_error) = (((ELF_E_HEADER) & 0xFF) | (
((0)) << 8)); } while (0);
56 return (0);
57 }
58
59 if ((uint64_t) e->e_rawsize < shoff + fsz) {
60 LIBELF_SET_ERROR(HEADER, 0)do { (_libelf.libelf_error) = (((ELF_E_HEADER) & 0xFF) | (
((0)) << 8)); } while (0);
61 return (0);
62 }
63
64 if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL((void *)0))
65 return (0);
66
67 xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec,
68 _libelf_elfmachine(e));
69 (*xlator)((unsigned char *) &scn->s_shdr, sizeof(scn->s_shdr),
70 (unsigned char *) e->e_rawfile + shoff, (size_t) 1,
71 e->e_byteorder != LIBELF_PRIVATE(byteorder)(_libelf.libelf_byteorder));
72
73#define GET_SHDR_MEMBER(M) ((ec == ELFCLASS321) ? scn->s_shdr.s_shdr32.M : \
74 scn->s_shdr.s_shdr64.M)
75
76 if ((shtype = GET_SHDR_MEMBER(sh_type)) != SHT_NULL0) {
Although the value stored to 'shtype' is used in the enclosing expression, the value is never actually read from 'shtype'
77 LIBELF_SET_ERROR(SECTION, 0)do { (_libelf.libelf_error) = (((ELF_E_SECTION) & 0xFF) |
(((0)) << 8)); } while (0);
78 return (0);
79 }
80
81 e->e_u.e_elf.e_nscn = (size_t) GET_SHDR_MEMBER(sh_size);
82 e->e_u.e_elf.e_nphdr = (phnum != PN_XNUM0xffff) ? phnum :
83 GET_SHDR_MEMBER(sh_info);
84 e->e_u.e_elf.e_strndx = (strndx != SHN_XINDEX0xffff) ? strndx :
85 GET_SHDR_MEMBER(sh_link);
86#undef GET_SHDR_MEMBER
87
88 return (1);
89}
90
91#define EHDR_INIT(E,SZ)do { ElfSZ_Ehdr *eh = (E); eh->e_ident[0] = 0x7f; eh->e_ident
[1] = 'E'; eh->e_ident[2] = 'L'; eh->e_ident[3] = 'F'; eh
->e_ident[4] = ELFCLASSSZ; eh->e_ident[5] = 0; eh->e_ident
[6] = (_libelf.libelf_version) & 0xFFU; eh->e_machine =
0; eh->e_type = ELF_K_NONE; eh->e_version = (_libelf.libelf_version
); } while (0) do { \
92 Elf##SZ##_Ehdr *eh = (E); \
93 eh->e_ident[EI_MAG00] = ELFMAG00x7f; \
94 eh->e_ident[EI_MAG11] = ELFMAG1'E'; \
95 eh->e_ident[EI_MAG22] = ELFMAG2'L'; \
96 eh->e_ident[EI_MAG33] = ELFMAG3'F'; \
97 eh->e_ident[EI_CLASS4] = ELFCLASS2##SZ; \
98 eh->e_ident[EI_DATA5] = ELFDATANONE0; \
99 eh->e_ident[EI_VERSION6] = LIBELF_PRIVATE(version)(_libelf.libelf_version) & 0xFFU; \
100 eh->e_machine = EM_NONE0; \
101 eh->e_type = ELF_K_NONE; \
102 eh->e_version = LIBELF_PRIVATE(version)(_libelf.libelf_version); \
103 } while (0)
104
105void *
106_libelf_ehdr(Elf *e, int ec, int allocate)
107{
108 void *ehdr;
109 size_t fsz, msz;
110 uint16_t phnum, shnum, strndx;
111 uint64_t shoff;
112 int (*xlator)(unsigned char *_d, size_t _dsz, unsigned char *_s,
113 size_t _c, int _swap);
114
115 assert(ec == ELFCLASS32 || ec == ELFCLASS64)((ec == 1 || ec == 2) ? (void)0 : __assert2("/usr/src/lib/libelf/libelf_ehdr.c"
, 115, __func__, "ec == ELFCLASS32 || ec == ELFCLASS64"));
116
117 if (e == NULL((void *)0) || e->e_kind != ELF_K_ELF) {
118 LIBELF_SET_ERROR(ARGUMENT, 0)do { (_libelf.libelf_error) = (((ELF_E_ARGUMENT) & 0xFF) |
(((0)) << 8)); } while (0);
119 return (NULL((void *)0));
120 }
121
122 if (e->e_class != ELFCLASSNONE0 && e->e_class != ec) {
123 LIBELF_SET_ERROR(CLASS, 0)do { (_libelf.libelf_error) = (((ELF_E_CLASS) & 0xFF) | (
((0)) << 8)); } while (0);
124 return (NULL((void *)0));
125 }
126
127 if (e->e_version != EV_CURRENT1) {
128 LIBELF_SET_ERROR(VERSION, 0)do { (_libelf.libelf_error) = (((ELF_E_VERSION) & 0xFF) |
(((0)) << 8)); } while (0);
129 return (NULL((void *)0));
130 }
131
132 if (e->e_class == ELFCLASSNONE0)
133 e->e_class = ec;
134
135 if (ec == ELFCLASS321)
136 ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr32;
137 else
138 ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr64;
139
140 if (ehdr != NULL((void *)0)) /* already have a translated ehdr */
141 return (ehdr);
142
143 fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1);
144 assert(fsz > 0)((fsz > 0) ? (void)0 : __assert2("/usr/src/lib/libelf/libelf_ehdr.c"
, 144, __func__, "fsz > 0"));
145
146 if (e->e_cmd != ELF_C_WRITE && e->e_rawsize < (off_t) fsz) {
147 LIBELF_SET_ERROR(HEADER, 0)do { (_libelf.libelf_error) = (((ELF_E_HEADER) & 0xFF) | (
((0)) << 8)); } while (0);
148 return (NULL((void *)0));
149 }
150
151 if ((msz = _libelf_msize(ELF_T_EHDR, ec, EV_CURRENT1)) == 0)
152 return (NULL((void *)0));
153
154 if ((ehdr = calloc((size_t) 1, msz)) == NULL((void *)0)) {
155 LIBELF_SET_ERROR(RESOURCE, 0)do { (_libelf.libelf_error) = (((ELF_E_RESOURCE) & 0xFF) |
(((0)) << 8)); } while (0);
156 return (NULL((void *)0));
157 }
158
159 if (ec == ELFCLASS321) {
160 e->e_u.e_elf.e_ehdr.e_ehdr32 = ehdr;
161 EHDR_INIT(ehdr,32)do { Elf32_Ehdr *eh = (ehdr); eh->e_ident[0] = 0x7f; eh->
e_ident[1] = 'E'; eh->e_ident[2] = 'L'; eh->e_ident[3] =
'F'; eh->e_ident[4] = 1; eh->e_ident[5] = 0; eh->e_ident
[6] = (_libelf.libelf_version) & 0xFFU; eh->e_machine =
0; eh->e_type = ELF_K_NONE; eh->e_version = (_libelf.libelf_version
); } while (0);
162 } else {
163 e->e_u.e_elf.e_ehdr.e_ehdr64 = ehdr;
164 EHDR_INIT(ehdr,64)do { Elf64_Ehdr *eh = (ehdr); eh->e_ident[0] = 0x7f; eh->
e_ident[1] = 'E'; eh->e_ident[2] = 'L'; eh->e_ident[3] =
'F'; eh->e_ident[4] = 2; eh->e_ident[5] = 0; eh->e_ident
[6] = (_libelf.libelf_version) & 0xFFU; eh->e_machine =
0; eh->e_type = ELF_K_NONE; eh->e_version = (_libelf.libelf_version
); } while (0);
165 }
166
167 if (allocate)
168 e->e_flags |= ELF_F_DIRTY0x002U;
169
170 if (e->e_cmd == ELF_C_WRITE)
171 return (ehdr);
172
173 xlator = _libelf_get_translator(ELF_T_EHDR, ELF_TOMEMORY, ec,
174 _libelf_elfmachine(e));
175 (*xlator)((unsigned char*) ehdr, msz, e->e_rawfile, (size_t) 1,
176 e->e_byteorder != LIBELF_PRIVATE(byteorder)(_libelf.libelf_byteorder));
177
178 if (ec == ELFCLASS321) {
179 phnum = ((Elf32_Ehdr *) ehdr)->e_phnum;
180 shnum = ((Elf32_Ehdr *) ehdr)->e_shnum;
181 shoff = ((Elf32_Ehdr *) ehdr)->e_shoff;
182 strndx = ((Elf32_Ehdr *) ehdr)->e_shstrndx;
183 } else {
184 phnum = ((Elf64_Ehdr *) ehdr)->e_phnum;
185 shnum = ((Elf64_Ehdr *) ehdr)->e_shnum;
186 shoff = ((Elf64_Ehdr *) ehdr)->e_shoff;
187 strndx = ((Elf64_Ehdr *) ehdr)->e_shstrndx;
188 }
189
190 if (shnum >= SHN_LORESERVE0xff00 ||
191 (shoff == 0LL && (shnum != 0 || phnum == PN_XNUM0xffff ||
192 strndx == SHN_XINDEX0xffff))) {
193 LIBELF_SET_ERROR(HEADER, 0)do { (_libelf.libelf_error) = (((ELF_E_HEADER) & 0xFF) | (
((0)) << 8)); } while (0);
194 return (NULL((void *)0));
195 }
196
197 /*
198 * If extended numbering is being used, read the correct
199 * number of sections and program header entries.
200 */
201 if ((shnum == 0 && shoff != 0) || phnum == PN_XNUM0xffff || strndx == SHN_XINDEX0xffff) {
202 if (_libelf_load_extended(e, ec, shoff, phnum, strndx) == 0)
203 return (NULL((void *)0));
204 } else {
205 /* not using extended numbering */
206 e->e_u.e_elf.e_nphdr = phnum;
207 e->e_u.e_elf.e_nscn = shnum;
208 e->e_u.e_elf.e_strndx = strndx;
209 }
210
211 return (ehdr);
212}