- Correctly handle sections of type SHT_NOBITS. For these sections:
- elf_getdata() and elf_rawdata() should return an "Elf_Data" structure that has its "d_buf" member set to NULL and "d_size" member set to the nominal 'size' of the section. [1] - Update the manual page for these functions. - Fix a memory leak in an error handling path inside elf_getdata(). - Use _libelf_allocate_data() in elf_newdata() for consistency. Obtained from: elftoolchain MFC after: 1 month
This commit is contained in:
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=210324
@ -39,7 +39,6 @@ Elf_Data *
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elf_getdata(Elf_Scn *s, Elf_Data *d)
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{
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Elf *e;
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char *dst;
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size_t fsz, msz, count;
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int elfclass, elftype;
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unsigned int sh_type;
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@ -79,20 +78,22 @@ elf_getdata(Elf_Scn *s, Elf_Data *d)
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sh_align = s->s_shdr.s_shdr64.sh_addralign;
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}
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if (sh_type == SHT_NULL)
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return (NULL);
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if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
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elftype > ELF_T_LAST ||
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sh_offset + sh_size > (uint64_t) e->e_rawsize) {
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elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
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sh_offset + sh_size > (uint64_t) e->e_rawsize)) {
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LIBELF_SET_ERROR(SECTION, 0);
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return (NULL);
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}
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if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)(elftype,
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(size_t) 1, e->e_version)) == 0) {
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if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
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(elftype, (size_t) 1, e->e_version)) == 0) {
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LIBELF_SET_ERROR(UNIMPL, 0);
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return (NULL);
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}
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if (sh_size % fsz) {
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LIBELF_SET_ERROR(SECTION, 0);
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return (NULL);
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@ -104,21 +105,25 @@ elf_getdata(Elf_Scn *s, Elf_Data *d)
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assert(msz > 0);
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if ((dst = malloc(msz*count)) == NULL) {
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LIBELF_SET_ERROR(RESOURCE, 0);
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return (NULL);
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}
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if ((d = _libelf_allocate_data(s)) == NULL)
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return (NULL);
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d->d_buf = dst;
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d->d_buf = NULL;
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d->d_off = 0;
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d->d_align = sh_align;
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d->d_size = msz * count;
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d->d_type = elftype;
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d->d_version = e->e_version;
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if (sh_type == SHT_NOBITS)
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return (d);
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if ((d->d_buf = malloc(msz*count)) == NULL) {
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(void) _libelf_release_data(d);
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LIBELF_SET_ERROR(RESOURCE, 0);
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return (NULL);
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}
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d->d_flags |= LIBELF_F_MALLOCED;
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STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
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@ -149,14 +154,10 @@ elf_newdata(Elf_Scn *s)
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if (elf_getdata(s, NULL) == NULL)
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return (NULL);
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if ((d = malloc(sizeof(Elf_Data))) == NULL) {
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LIBELF_SET_ERROR(RESOURCE, errno);
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if ((d = _libelf_allocate_data(s)) == NULL)
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return (NULL);
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}
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STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
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d->d_flags = 0;
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d->d_scn = s;
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d->d_align = 1;
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d->d_buf = NULL;
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@ -180,6 +181,7 @@ elf_rawdata(Elf_Scn *s, Elf_Data *d)
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{
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Elf *e;
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int elf_class;
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uint32_t sh_type;
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uint64_t sh_align, sh_offset, sh_size;
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if (s == NULL || (e = s->s_elf) == NULL ||
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@ -199,19 +201,24 @@ elf_rawdata(Elf_Scn *s, Elf_Data *d)
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assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64);
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if (elf_class == ELFCLASS32) {
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sh_type = s->s_shdr.s_shdr32.sh_type;
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sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
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sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
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sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
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} else {
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sh_type = s->s_shdr.s_shdr64.sh_type;
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sh_offset = s->s_shdr.s_shdr64.sh_offset;
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sh_size = s->s_shdr.s_shdr64.sh_size;
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sh_align = s->s_shdr.s_shdr64.sh_addralign;
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}
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if (sh_type == SHT_NULL)
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return (NULL);
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if ((d = _libelf_allocate_data(s)) == NULL)
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return (NULL);
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d->d_buf = e->e_rawfile + sh_offset;
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d->d_buf = sh_type == SHT_NOBITS ? NULL : e->e_rawfile + sh_offset;
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d->d_off = 0;
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d->d_align = sh_align;
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d->d_size = sh_size;
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@ -1,4 +1,4 @@
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.\" Copyright (c) 2006 Joseph Koshy. All rights reserved.
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.\" Copyright (c) 2006,2008 Joseph Koshy. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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@ -142,6 +142,32 @@ always returns
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.Vt Elf_Data
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structures of type
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.Dv ELF_T_BYTE .
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.Ss Special handling of SHT_NOBITS sections
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For sections of type
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.Dv SHT_NOBITS ,
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the functions
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.Fn elf_getdata
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and
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.Fn elf_rawdata
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return a pointer to a valid
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.Vt Elf_Data
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structure that has its
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.Va d_buf
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member set to NULL and its
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.Va d_size
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member set to the size of the section.
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.Pp
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If an application wishes to create a section of type
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.Dv SHT_NOBITS ,
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it should add a data buffer to the section using function
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.Fn elf_newdata .
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It should then set the
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.Va d_buf
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and
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.Va d_size
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members of the returned
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.Vt Elf_Data
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structure to NULL and the desired size of the section respectively.
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.Sh RETURN VALUES
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These functions return a valid pointer to a data descriptor if successful, or
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NULL if an error occurs.
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