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binfmt_flat: use proper user space accessors with relocs processing code 

Relocs are fixed up in place in user space memory.  The appropriate
accessors are required for this code to work with an active MMU.

The architecture specific handlers flat_get_addr_from_rp() and
flat_put_addr_at_rp() for ARM and M68K are adjusted with separate
patches. SuperH and Xtensa are left out as they doesn't implement
__get_user_unaligned() and __put_user_unaligned() yet. The other
architectures that use BFLT don't have any MMU.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
This commit is contained in:
Nicolas Pitre 2016-07-24 11:30:21 -04:00 committed by Greg Ungerer
parent a97d157d00
commit 6e572ffe3f
1 changed files with 19 additions and 12 deletions
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31
fs/binfmt_flat.c
View File

@ -419,7 +419,7 @@ static int load_flat_file(struct linux_binprm *bprm,
unsigned long textpos, datapos, realdatastart;
unsigned long text_len, data_len, bss_len, stack_len, full_data, flags;
unsigned long len, memp, memp_size, extra, rlim;
unsigned long *reloc, *rp;
unsigned long __user *reloc, *rp;
struct inode *inode;
int i, rev, relocs;
loff_t fpos;
@ -591,7 +591,7 @@ static int load_flat_file(struct linux_binprm *bprm,
goto err;
}
reloc = (unsigned long *)
reloc = (unsigned long __user *)
(datapos + (ntohl(hdr->reloc_start) - text_len));
memp = realdatastart;
memp_size = len;
@ -616,7 +616,7 @@ static int load_flat_file(struct linux_binprm *bprm,
MAX_SHARED_LIBS * sizeof(unsigned long),
FLAT_DATA_ALIGN);
reloc = (unsigned long *)
reloc = (unsigned long __user *)
(datapos + (ntohl(hdr->reloc_start) - text_len));
memp = textpos;
memp_size = len;
@ -708,15 +708,20 @@ static int load_flat_file(struct linux_binprm *bprm,
* image.
*/
if (flags & FLAT_FLAG_GOTPIC) {
for (rp = (unsigned long *)datapos; *rp != 0xffffffff; rp++) {
unsigned long addr;
if (*rp) {
addr = calc_reloc(*rp, libinfo, id, 0);
for (rp = (unsigned long __user *)datapos; ; rp++) {
unsigned long addr, rp_val;
if (get_user(rp_val, rp))
return -EFAULT;
if (rp_val == 0xffffffff)
break;
if (rp_val) {
addr = calc_reloc(rp_val, libinfo, id, 0);
if (addr == RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}
*rp = addr;
if (put_user(addr, rp))
return -EFAULT;
}
}
}
@ -733,7 +738,7 @@ static int load_flat_file(struct linux_binprm *bprm,
* __start to address 4 so that is okay).
*/
if (rev > OLD_FLAT_VERSION) {
unsigned long persistent = 0;
unsigned long __maybe_unused persistent = 0;
for (i = 0; i < relocs; i++) {
unsigned long addr, relval;
@ -742,12 +747,14 @@ static int load_flat_file(struct linux_binprm *bprm,
* relocated (of course, the address has to be
* relocated first).
*/
relval = ntohl(reloc[i]);
if (get_user(relval, reloc + i))
return -EFAULT;
relval = ntohl(relval);
if (flat_set_persistent(relval, &persistent))
continue;
addr = flat_get_relocate_addr(relval);
rp = (unsigned long *) calc_reloc(addr, libinfo, id, 1);
if (rp == (unsigned long *)RELOC_FAILED) {
rp = (unsigned long __user *)calc_reloc(addr, libinfo, id, 1);
if (rp == (unsigned long __user *)RELOC_FAILED) {
ret = -ENOEXEC;
goto err;
}