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-rw-r--r--libelf/elf_getdata.c133
1 files changed, 90 insertions, 43 deletions
diff --git a/libelf/elf_getdata.c b/libelf/elf_getdata.c
index 0aeb9972..9a567e51 100644
--- a/libelf/elf_getdata.c
+++ b/libelf/elf_getdata.c
@@ -1,5 +1,5 @@
/* Return the next data element from the section after possibly converting it.
- Copyright (C) 1998-2005, 2006, 2007 Red Hat, Inc.
+ Copyright (C) 1998-2005, 2006, 2007, 2015 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <drepper@redhat.com>, 1998.
@@ -83,8 +83,15 @@ const uint_fast8_t __libelf_type_aligns[EV_NUM - 1][ELFCLASSNUM - 1][ELF_T_NUM]
# define TYPE_ALIGNS(Bits) \
{ \
[ELF_T_ADDR] = __alignof__ (ElfW2(Bits,Addr)), \
+ [ELF_T_EHDR] = __alignof__ (ElfW2(Bits,Ehdr)), \
[ELF_T_HALF] = __alignof__ (ElfW2(Bits,Half)), \
+ [ELF_T_OFF] = __alignof__ (ElfW2(Bits,Off)), \
+ [ELF_T_PHDR] = __alignof__ (ElfW2(Bits,Phdr)), \
+ [ELF_T_SHDR] = __alignof__ (ElfW2(Bits,Shdr)), \
+ [ELF_T_SWORD] = __alignof__ (ElfW2(Bits,Sword)), \
[ELF_T_WORD] = __alignof__ (ElfW2(Bits,Word)), \
+ [ELF_T_XWORD] = __alignof__ (ElfW2(Bits,Xword)), \
+ [ELF_T_SXWORD] = __alignof__ (ElfW2(Bits,Sxword)), \
[ELF_T_SYM] = __alignof__ (ElfW2(Bits,Sym)), \
[ELF_T_SYMINFO] = __alignof__ (ElfW2(Bits,Syminfo)), \
[ELF_T_REL] = __alignof__ (ElfW2(Bits,Rel)), \
@@ -97,6 +104,8 @@ const uint_fast8_t __libelf_type_aligns[EV_NUM - 1][ELFCLASSNUM - 1][ELF_T_NUM]
[ELF_T_MOVE] = __alignof__ (ElfW2(Bits,Move)), \
[ELF_T_LIB] = __alignof__ (ElfW2(Bits,Lib)), \
[ELF_T_NHDR] = __alignof__ (ElfW2(Bits,Nhdr)), \
+ [ELF_T_GNUHASH] = __alignof__ (Elf32_Word), \
+ [ELF_T_AUXV] = __alignof__ (ElfW2(Bits,auxv_t)), \
}
[EV_CURRENT - 1] =
{
@@ -144,6 +153,25 @@ convert_data (Elf_Scn *scn, int version __attribute__ ((unused)), int eclass,
return;
}
+ /* Make sure the source is correctly aligned for the conversion
+ function to directly access the data elements. */
+ char *rawdata_source;
+ if (ALLOW_UNALIGNED ||
+ ((((size_t) (char *) scn->rawdata_base)) & (align - 1)) == 0)
+ rawdata_source = scn->rawdata_base;
+ else
+ {
+ rawdata_source = (char *) malloc (size);
+ if (rawdata_source == NULL)
+ {
+ __libelf_seterrno (ELF_E_NOMEM);
+ return;
+ }
+
+ /* The copy will be appropriately aligned for direct access. */
+ memcpy (rawdata_source, scn->rawdata_base, size);
+ }
+
/* Get the conversion function. */
#if EV_NUM != 2
fp = __elf_xfctstom[version - 1][__libelf_version - 1][eclass - 1][type];
@@ -151,7 +179,10 @@ convert_data (Elf_Scn *scn, int version __attribute__ ((unused)), int eclass,
fp = __elf_xfctstom[0][0][eclass - 1][type];
#endif
- fp (scn->data_base, scn->rawdata_base, size, 0);
+ fp (scn->data_base, rawdata_source, size, 0);
+
+ if (rawdata_source != scn->rawdata_base)
+ free (rawdata_source);
}
scn->data_list.data.d.d_buf = scn->data_base;
@@ -301,6 +332,20 @@ __libelf_set_rawdata_wrlock (Elf_Scn *scn)
else
scn->rawdata.d.d_type = shtype_map[LIBELF_EV_IDX][TYPEIDX (type)];
scn->rawdata.d.d_off = 0;
+
+ /* Make sure the alignment makes sense. d_align should be aligned both
+ in the section (trivially true since d_off is zero) and in the file.
+ Unfortunately we cannot be too strict because there are ELF files
+ out there that fail this requirement. We will try to fix those up
+ in elf_update when writing out the image. But for very large
+ alignment values this can bloat the image considerably. So here
+ just check and clamp the alignment value to not be bigger than the
+ actual offset of the data in the file. Given that there is always
+ at least an ehdr this will only trigger for alignment values > 64
+ which should be uncommon. */
+ align = align ?: 1;
+ if (align > offset)
+ align = offset;
scn->rawdata.d.d_align = align;
if (elf->class == ELFCLASS32
|| (offsetof (struct Elf, state.elf32.ehdr)
@@ -337,11 +382,47 @@ __libelf_set_rawdata (Elf_Scn *scn)
return result;
}
+void
+internal_function
+__libelf_set_data_list_rdlock (Elf_Scn *scn, int wrlocked)
+{
+ if (scn->rawdata.d.d_buf != NULL && scn->rawdata.d.d_size > 0)
+ {
+ Elf *elf = scn->elf;
+
+ /* Upgrade the lock to a write lock if necessary and check
+ nobody else already did the work. */
+ if (!wrlocked)
+ {
+ rwlock_unlock (elf->lock);
+ rwlock_wrlock (elf->lock);
+ if (scn->data_list_rear != NULL)
+ return;
+ }
+
+ /* Convert according to the version and the type. */
+ convert_data (scn, __libelf_version, elf->class,
+ (elf->class == ELFCLASS32
+ || (offsetof (struct Elf, state.elf32.ehdr)
+ == offsetof (struct Elf, state.elf64.ehdr))
+ ? elf->state.elf32.ehdr->e_ident[EI_DATA]
+ : elf->state.elf64.ehdr->e_ident[EI_DATA]),
+ scn->rawdata.d.d_size, scn->rawdata.d.d_type);
+ }
+ else
+ {
+ /* This is an empty or NOBITS section. There is no buffer but
+ the size information etc is important. */
+ scn->data_list.data.d = scn->rawdata.d;
+ scn->data_list.data.s = scn;
+ }
+
+ scn->data_list_rear = &scn->data_list;
+}
+
Elf_Data *
internal_function
-__elf_getdata_rdlock (scn, data)
- Elf_Scn *scn;
- Elf_Data *data;
+__elf_getdata_rdlock (Elf_Scn *scn, Elf_Data *data)
{
Elf_Data *result = NULL;
Elf *elf;
@@ -427,51 +508,17 @@ __elf_getdata_rdlock (scn, data)
empty in case the section has size zero (for whatever reason).
Now create the converted data in case this is necessary. */
if (scn->data_list_rear == NULL)
- {
- if (scn->rawdata.d.d_buf != NULL && scn->rawdata.d.d_size > 0)
- {
- if (!locked)
- {
- rwlock_unlock (elf->lock);
- rwlock_wrlock (elf->lock);
- if (scn->data_list_rear != NULL)
- goto pass;
- }
-
- /* Convert according to the version and the type. */
- convert_data (scn, __libelf_version, elf->class,
- (elf->class == ELFCLASS32
- || (offsetof (struct Elf, state.elf32.ehdr)
- == offsetof (struct Elf, state.elf64.ehdr))
- ? elf->state.elf32.ehdr->e_ident[EI_DATA]
- : elf->state.elf64.ehdr->e_ident[EI_DATA]),
- scn->rawdata.d.d_size, scn->rawdata.d.d_type);
- }
- else
- {
- /* This is an empty or NOBITS section. There is no buffer but
- the size information etc is important. */
- scn->data_list.data.d = scn->rawdata.d;
- scn->data_list.data.s = scn;
- }
-
- scn->data_list_rear = &scn->data_list;
- }
+ __libelf_set_data_list_rdlock (scn, locked);
- /* If no data is present we cannot return any. */
- if (scn->data_list_rear != NULL)
- pass:
- /* Return the first data element in the list. */
- result = &scn->data_list.data.d;
+ /* Return the first data element in the list. */
+ result = &scn->data_list.data.d;
out:
return result;
}
Elf_Data *
-elf_getdata (scn, data)
- Elf_Scn *scn;
- Elf_Data *data;
+elf_getdata (Elf_Scn *scn, Elf_Data *data)
{
Elf_Data *result;
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-24 15:29:11 +0000