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linux-user/elfload: Parse NT_GNU_PROPERTY_TYPE_0 notes

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This is generic support, with the code disabled for all targets.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201021173749.111103-11-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2020-10-21 10:37:47 -07:00 committed by Peter Maydell
parent 808f656318
commit 83f990eb5a
2 changed files with 161 additions and 0 deletions
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157
linux-user/elfload.c
View File

@ -1522,6 +1522,15 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs,
#include "elf.h"
static bool arch_parse_elf_property(uint32_t pr_type, uint32_t pr_datasz,
const uint32_t *data,
struct image_info *info,
Error **errp)
{
g_assert_not_reached();
}
#define ARCH_USE_GNU_PROPERTY 0
struct exec
{
unsigned int a_info; /* Use macros N_MAGIC, etc for access */
@ -2373,6 +2382,150 @@ void probe_guest_base(const char *image_name, abi_ulong guest_loaddr,
"@ 0x%" PRIx64 "\n", (uint64_t)guest_base);
}
enum {
/* The string "GNU\0" as a magic number. */
GNU0_MAGIC = const_le32('G' | 'N' << 8 | 'U' << 16),
NOTE_DATA_SZ = 1 * KiB,
NOTE_NAME_SZ = 4,
ELF_GNU_PROPERTY_ALIGN = ELF_CLASS == ELFCLASS32 ? 4 : 8,
};
/*
* Process a single gnu_property entry.
* Return false for error.
*/
static bool parse_elf_property(const uint32_t *data, int *off, int datasz,
struct image_info *info, bool have_prev_type,
uint32_t *prev_type, Error **errp)
{
uint32_t pr_type, pr_datasz, step;
if (*off > datasz || !QEMU_IS_ALIGNED(*off, ELF_GNU_PROPERTY_ALIGN)) {
goto error_data;
}
datasz -= *off;
data += *off / sizeof(uint32_t);
if (datasz < 2 * sizeof(uint32_t)) {
goto error_data;
}
pr_type = data[0];
pr_datasz = data[1];
data += 2;
datasz -= 2 * sizeof(uint32_t);
step = ROUND_UP(pr_datasz, ELF_GNU_PROPERTY_ALIGN);
if (step > datasz) {
goto error_data;
}
/* Properties are supposed to be unique and sorted on pr_type. */
if (have_prev_type && pr_type <= *prev_type) {
if (pr_type == *prev_type) {
error_setg(errp, "Duplicate property in PT_GNU_PROPERTY");
} else {
error_setg(errp, "Unsorted property in PT_GNU_PROPERTY");
}
return false;
}
*prev_type = pr_type;
if (!arch_parse_elf_property(pr_type, pr_datasz, data, info, errp)) {
return false;
}
*off += 2 * sizeof(uint32_t) + step;
return true;
error_data:
error_setg(errp, "Ill-formed property in PT_GNU_PROPERTY");
return false;
}
/* Process NT_GNU_PROPERTY_TYPE_0. */
static bool parse_elf_properties(int image_fd,
struct image_info *info,
const struct elf_phdr *phdr,
char bprm_buf[BPRM_BUF_SIZE],
Error **errp)
{
union {
struct elf_note nhdr;
uint32_t data[NOTE_DATA_SZ / sizeof(uint32_t)];
} note;
int n, off, datasz;
bool have_prev_type;
uint32_t prev_type;
/* Unless the arch requires properties, ignore them. */
if (!ARCH_USE_GNU_PROPERTY) {
return true;
}
/* If the properties are crazy large, that's too bad. */
n = phdr->p_filesz;
if (n > sizeof(note)) {
error_setg(errp, "PT_GNU_PROPERTY too large");
return false;
}
if (n < sizeof(note.nhdr)) {
error_setg(errp, "PT_GNU_PROPERTY too small");
return false;
}
if (phdr->p_offset + n <= BPRM_BUF_SIZE) {
memcpy(&note, bprm_buf + phdr->p_offset, n);
} else {
ssize_t len = pread(image_fd, &note, n, phdr->p_offset);
if (len != n) {
error_setg_errno(errp, errno, "Error reading file header");
return false;
}
}
/*
* The contents of a valid PT_GNU_PROPERTY is a sequence
* of uint32_t -- swap them all now.
*/
#ifdef BSWAP_NEEDED
for (int i = 0; i < n / 4; i++) {
bswap32s(note.data + i);
}
#endif
/*
* Note that nhdr is 3 words, and that the "name" described by namesz
* immediately follows nhdr and is thus at the 4th word. Further, all
* of the inputs to the kernel's round_up are multiples of 4.
*/
if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 ||
note.nhdr.n_namesz != NOTE_NAME_SZ ||
note.data[3] != GNU0_MAGIC) {
error_setg(errp, "Invalid note in PT_GNU_PROPERTY");
return false;
}
off = sizeof(note.nhdr) + NOTE_NAME_SZ;
datasz = note.nhdr.n_descsz + off;
if (datasz > n) {
error_setg(errp, "Invalid note size in PT_GNU_PROPERTY");
return false;
}
have_prev_type = false;
prev_type = 0;
while (1) {
if (off == datasz) {
return true; /* end, exit ok */
}
if (!parse_elf_property(note.data, &off, datasz, info,
have_prev_type, &prev_type, errp)) {
return false;
}
have_prev_type = true;
}
}
/* Load an ELF image into the address space.
IMAGE_NAME is the filename of the image, to use in error messages.
@ -2467,6 +2620,10 @@ static void load_elf_image(const char *image_name, int image_fd,
goto exit_errmsg;
}
*pinterp_name = g_steal_pointer(&interp_name);
} else if (eppnt->p_type == PT_GNU_PROPERTY) {
if (!parse_elf_properties(image_fd, info, eppnt, bprm_buf, &err)) {
goto exit_errmsg;
}
}
}

4
linux-user/qemu.h
View File

@ -61,6 +61,10 @@ struct image_info {
abi_ulong interpreter_loadmap_addr;
abi_ulong interpreter_pt_dynamic_addr;
struct image_info *other_info;
/* For target-specific processing of NT_GNU_PROPERTY_TYPE_0. */
uint32_t note_flags;
#ifdef TARGET_MIPS
int fp_abi;
int interp_fp_abi;