Merge pull request #1206 from stefanrueger/nsafety

Fix reading of .elf files
This commit is contained in:
Stefan Rueger 2022-12-14 00:06:47 +00:00 committed by GitHub
commit 72f097502f
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1 changed files with 77 additions and 94 deletions

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@ -118,10 +118,9 @@ char * fileio_fmtstr(FILEFMT format)
} }
static int b2ihex(const unsigned char *inbuf, int bufsize, static int b2ihex(const unsigned char *inbuf, int bufsize, int recsize,
int recsize, int startaddr, int startaddr, const char *outfile_unused, FILE *outf, FILEFMT ffmt) {
const char *outfile, FILE *outf, FILEFMT ffmt)
{
const unsigned char *buf; const unsigned char *buf;
unsigned int nextaddr; unsigned int nextaddr;
int n, nbytes, n_64k; int n, nbytes, n_64k;
@ -397,10 +396,9 @@ static int ihex2b(const char *infile, FILE *inf,
} }
} }
static int b2srec(const unsigned char *inbuf, int bufsize, static int b2srec(const unsigned char *inbuf, int bufsize, int recsize,
int recsize, int startaddr, int startaddr, const char *outfile_unused, FILE *outf) {
const char *outfile, FILE *outf)
{
const unsigned char *buf; const unsigned char *buf;
unsigned int nextaddr; unsigned int nextaddr;
int n, nbytes, addr_width; int n, nbytes, addr_width;
@ -708,41 +706,6 @@ int is_section_in_segment(Elf32_Shdr *sh, Elf32_Phdr *ph)
return 1; return 1;
} }
/*
* Return the ELF section descriptor that corresponds to program
* header `ph'. The program header is expected to be of p_type
* PT_LOAD, and to have a nonzero p_filesz. (PT_LOAD sections with a
* zero p_filesz are typically RAM sections that are not initialized
* by file data, e.g. ".bss".)
*/
static Elf_Scn *elf_get_scn(Elf *e, Elf32_Phdr *ph, Elf32_Shdr **shptr)
{
Elf_Scn *s = NULL;
while ((s = elf_nextscn(e, s)) != NULL) {
Elf32_Shdr *sh;
size_t ndx = elf_ndxscn(s);
if ((sh = elf32_getshdr(s)) == NULL) {
pmsg_error("unable to read section #%u header: %s\n", (unsigned int)ndx, elf_errmsg(-1));
continue;
}
if ((sh->sh_flags & SHF_ALLOC) == 0 ||
sh->sh_type != SHT_PROGBITS)
/* we are only interested in PROGBITS, ALLOC sections */
continue;
if (sh->sh_size == 0)
/* we are not interested in empty sections */
continue;
if (is_section_in_segment(sh, ph)) {
/* yeah, we found it */
*shptr = sh;
return s;
}
}
pmsg_error("cannot find a matching section for program header entry @p_vaddr 0x%x\n", ph->p_vaddr);
return NULL;
}
static int elf_mem_limits(const AVRMEM *mem, const AVRPART *p, static int elf_mem_limits(const AVRMEM *mem, const AVRPART *p,
unsigned int *lowbound, unsigned int *lowbound,
@ -765,13 +728,17 @@ static int elf_mem_limits(const AVRMEM *mem, const AVRPART *p,
strcmp(mem->desc, "application") == 0 || strcmp(mem->desc, "application") == 0 ||
strcmp(mem->desc, "apptable") == 0) { strcmp(mem->desc, "apptable") == 0) {
*lowbound = 0; *lowbound = 0;
*highbound = 0x7ffff; /* max 8 MiB */ *highbound = 0x7Fffff; // Max 8 MiB
*fileoff = 0;
} else if (strcmp(mem->desc, "data") == 0) { // SRAM for XMEGAs
*lowbound = 0x802000;
*highbound = 0x80ffff;
*fileoff = 0; *fileoff = 0;
} else if (strcmp(mem->desc, "eeprom") == 0) { } else if (strcmp(mem->desc, "eeprom") == 0) {
*lowbound = 0x810000; *lowbound = 0x810000;
*highbound = 0x81ffff; /* max 64 KiB */ *highbound = 0x81ffff; // Max 64 KiB
*fileoff = 0; *fileoff = 0;
} else if (strcmp(mem->desc, "lfuse") == 0) { } else if (strcmp(mem->desc, "lfuse") == 0 || strcmp(mem->desc, "fuses") == 0) {
*lowbound = 0x820000; *lowbound = 0x820000;
*highbound = 0x82ffff; *highbound = 0x82ffff;
*fileoff = 0; *fileoff = 0;
@ -789,10 +756,18 @@ static int elf_mem_limits(const AVRMEM *mem, const AVRPART *p,
*lowbound = 0x820000; *lowbound = 0x820000;
*highbound = 0x82ffff; *highbound = 0x82ffff;
*fileoff = mem->desc[4] - '0'; *fileoff = mem->desc[4] - '0';
} else if (strncmp(mem->desc, "lock", 4) == 0) { } else if (strncmp(mem->desc, "lock", 4) == 0) { // Lock or lockbits
*lowbound = 0x830000; *lowbound = 0x830000;
*highbound = 0x83ffff; *highbound = 0x83ffff;
*fileoff = 0; *fileoff = 0;
} else if (strcmp(mem->desc, "signature") == 0) { // Read only
*lowbound = 0x840000;
*highbound = 0x84ffff;
*fileoff = 0;
} else if (strncmp(mem->desc, "user", 4) == 0) { // Usersig or userrow
*lowbound = 0x850000;
*highbound = 0x85ffff;
*fileoff = 0;
} else { } else {
rv = -1; rv = -1;
} }
@ -802,12 +777,11 @@ static int elf_mem_limits(const AVRMEM *mem, const AVRPART *p,
} }
static int elf2b(const char *infile, FILE *inf, static int elf2b(const char *infile, FILE *inf, const AVRMEM *mem,
const AVRMEM *mem, const AVRPART *p, const AVRPART *p, int bufsize_unused, unsigned int fileoffset_unused) {
int bufsize, unsigned int fileoffset)
{
Elf *e; Elf *e;
int rv = -1; int rv = 0, size = 0;
unsigned int low, high, foff; unsigned int low, high, foff;
if (elf_mem_limits(mem, p, &low, &high, &foff) != 0) { if (elf_mem_limits(mem, p, &low, &high, &foff) != 0) {
@ -919,37 +893,39 @@ static int elf2b(const char *infile, FILE *inf,
* PT_LOAD, and have a non-zero p_filesz. * PT_LOAD, and have a non-zero p_filesz.
*/ */
for (i = 0; i < eh->e_phnum; i++) { for (i = 0; i < eh->e_phnum; i++) {
if (ph[i].p_type != PT_LOAD || if (ph[i].p_type != PT_LOAD || ph[i].p_filesz == 0)
ph[i].p_filesz == 0)
continue; continue;
pmsg_notice2("considering PT_LOAD program header entry #%d:\n" pmsg_notice2("considering PT_LOAD program header entry #%d\n", (int) i);
" p_vaddr 0x%x, p_paddr 0x%x, p_filesz %d\n", (int) i, ph[i].p_vaddr, ph[i].p_paddr, ph[i].p_filesz); imsg_notice2("p_vaddr 0x%x, p_paddr 0x%x, p_filesz %d\n", ph[i].p_vaddr, ph[i].p_paddr, ph[i].p_filesz);
Elf32_Shdr *sh; Elf_Scn *scn = NULL;
Elf_Scn *s = elf_get_scn(e, ph + i, &sh); while ((scn = elf_nextscn(e, scn)) != NULL) {
if (s == NULL) size_t ndx = elf_ndxscn(scn);
Elf32_Shdr *sh = elf32_getshdr(scn);
if (sh == NULL) {
pmsg_error("unable to read section #%u header: %s\n", (unsigned int) ndx, elf_errmsg(-1));
rv = -1;
continue; continue;
if ((sh->sh_flags & SHF_ALLOC) && sh->sh_size) {
const char *sname;
if (sndx != 0) {
sname = elf_strptr(e, sndx, sh->sh_name);
} else {
sname = "*unknown*";
} }
// Only interested in PROGBITS, ALLOC sections
if ((sh->sh_flags & SHF_ALLOC) == 0 || sh->sh_type != SHT_PROGBITS)
continue;
// Not interested in empty sections
if (sh->sh_size == 0)
continue;
// Section must belong to this segment
if (!is_section_in_segment(sh, ph+i))
continue;
unsigned int lma; const char *sname = sndx? elf_strptr(e, sndx, sh->sh_name): "*unknown*";
lma = ph[i].p_paddr + sh->sh_offset - ph[i].p_offset; unsigned int lma = ph[i].p_paddr + sh->sh_offset - ph[i].p_offset;
pmsg_notice2("found section %s, LMA 0x%x, sh_size %u\n", sname, lma, sh->sh_size); pmsg_notice2("found section %s, LMA 0x%x, sh_size %u\n", sname, lma, sh->sh_size);
if (lma >= low && if(!(lma >= low && lma + sh->sh_size < high)) {
lma + sh->sh_size < high) { imsg_notice2("skipping %s (inappropriate for %s)\n", sname, mem->desc);
/* OK */
} else {
msg_notice2(" => skipping, inappropriate for %s memory region\n", mem->desc);
continue; continue;
} }
/* /*
@ -961,44 +937,51 @@ static int elf2b(const char *infile, FILE *inf,
* from it, using the "foff" offset obtained above. * from it, using the "foff" offset obtained above.
*/ */
if (mem->size != 1 && sh->sh_size > (unsigned) mem->size) { if (mem->size != 1 && sh->sh_size > (unsigned) mem->size) {
pmsg_error("section %s does not fit into %s memory:\n" pmsg_error("section %s of size %u does not fit into %s of size %d\n",
" 0x%x + %u > %u\n", sname, mem->desc, lma, sh->sh_size, mem->size); sname, sh->sh_size, mem->desc, mem->size);
rv = -1;
continue; continue;
} }
Elf_Data *d = NULL; Elf_Data *d = NULL;
while ((d = elf_getdata(s, d)) != NULL) { while ((d = elf_getdata(scn, d)) != NULL) {
msg_notice2(" Data block: d_buf %p, d_off 0x%x, d_size %ld\n", imsg_notice2("data block: d_buf %p, d_off 0x%x, d_size %ld\n",
d->d_buf, (unsigned int)d->d_off, (long) d->d_size); d->d_buf, (unsigned int)d->d_off, (long) d->d_size);
if (mem->size == 1) { if (mem->size == 1) {
if (d->d_off != 0) { if (d->d_off != 0) {
pmsg_error("unexpected data block at offset != 0\n"); pmsg_error("unexpected data block at offset != 0\n");
rv = -1;
} else if (foff >= d->d_size) { } else if (foff >= d->d_size) {
pmsg_error("ELF file section does not contain byte at offset %d\n", foff); pmsg_error("ELF file section does not contain byte at offset %d\n", foff);
rv = -1;
} else { } else {
msg_notice2(" Extracting one byte from file offset %d\n", imsg_notice2("extracting one byte from file offset %d\n", foff);
foff);
mem->buf[0] = ((unsigned char *)d->d_buf)[foff]; mem->buf[0] = ((unsigned char *)d->d_buf)[foff];
mem->tags[0] = TAG_ALLOCATED; mem->tags[0] = TAG_ALLOCATED;
rv = 1; size = 1;
} }
} else { } else {
unsigned int idx; int idx = lma-low + d->d_off;
int end = idx + d->d_size;
idx = lma - low + d->d_off; if(idx >= 0 && idx < mem->size && end >= 0 && end <= mem->size && end-idx >= 0) {
if ((int)(idx + d->d_size) > rv) if (end > size)
rv = idx + d->d_size; size = end;
msg_debug(" Writing %ld bytes to mem offset 0x%x\n", imsg_debug("writing %d bytes to mem offset 0x%x\n", end-idx, idx);
(long) d->d_size, idx); memcpy(mem->buf + idx, d->d_buf, end-idx);
memcpy(mem->buf + idx, d->d_buf, d->d_size); memset(mem->tags + idx, TAG_ALLOCATED, end-idx);
memset(mem->tags + idx, TAG_ALLOCATED, d->d_size); } else {
pmsg_error("section %s [0x%04x, 0x%04x] does not fit into %s [0, 0x%04x]\n",
sname, idx, (int) (idx + d->d_size-1), mem->desc, mem->size-1);
rv = -1;
}
} }
} }
} }
} }
done: done:
(void)elf_end(e); (void)elf_end(e);
return rv; return rv<0? rv: size;
} }
#endif /* HAVE_LIBELF */ #endif /* HAVE_LIBELF */
@ -1071,9 +1054,9 @@ static int fileio_rbin(struct fioparms *fio,
} }
static int fileio_imm(struct fioparms *fio, static int fileio_imm(struct fioparms *fio, const char *fname, FILE *f_unused,
const char *fname, FILE *f, const AVRMEM *mem, int size) const AVRMEM *mem, int size) {
{
int rc = 0; int rc = 0;
char *e, *p, *filename; char *e, *p, *filename;
unsigned long b; unsigned long b;