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binfmt_flat: use proper user space accessors with relocs processing code

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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
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@ -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;
}