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Groups > linux.kernel > #1441750
| From | Nicolas Pitre <nicolas.pitre@linaro.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 05/10] binfmt_flat: use proper user space accessors with relocs processing code |
| Date | 2016-07-12 23:50 +0200 |
| Message-ID | <rUdJ0-293-19@gated-at.bofh.it> (permalink) |
| References | <rUdIZ-293-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Relocs are fixed up in place in user space memory. The appropriate
accessors are required for this code to work with an active MMU.
Only those architectures with trivial architecture-specific handlers are
covered by this patch. Incidentally, those NOMMU architectures that can
also have a MMU are amongst the trivial ones so it should be fine.
---
arch/arm/include/asm/flat.h | 5 +++--
arch/m68k/include/asm/flat.h | 5 +++--
arch/sh/include/asm/flat.h | 5 +++--
arch/xtensa/include/asm/flat.h | 5 +++--
fs/binfmt_flat.c | 31 +++++++++++++++++++------------
5 files changed, 31 insertions(+), 20 deletions(-)
diff --git a/arch/arm/include/asm/flat.h b/arch/arm/include/asm/flat.h
index e847d23351..acf1d14b89 100644
--- a/arch/arm/include/asm/flat.h
+++ b/arch/arm/include/asm/flat.h
@@ -8,8 +8,9 @@
#define flat_argvp_envp_on_stack() 1
#define flat_old_ram_flag(flags) (flags)
#define flat_reloc_valid(reloc, size) ((reloc) <= (size))
-#define flat_get_addr_from_rp(rp, relval, flags, persistent) ((void)persistent,get_unaligned(rp))
-#define flat_put_addr_at_rp(rp, val, relval) put_unaligned(val,rp)
+#define flat_get_addr_from_rp(rp, relval, flags, persistent) \
+ ({ unsigned long __val; __get_user_unaligned(__val, rp); __val; })
+#define flat_put_addr_at_rp(rp, val, relval) __put_user_unaligned(val, rp)
#define flat_get_relocate_addr(rel) (rel)
#define flat_set_persistent(relval, p) 0
diff --git a/arch/m68k/include/asm/flat.h b/arch/m68k/include/asm/flat.h
index f9454b89a5..f3f592d03e 100644
--- a/arch/m68k/include/asm/flat.h
+++ b/arch/m68k/include/asm/flat.h
@@ -8,8 +8,9 @@
#define flat_argvp_envp_on_stack() 1
#define flat_old_ram_flag(flags) (flags)
#define flat_reloc_valid(reloc, size) ((reloc) <= (size))
-#define flat_get_addr_from_rp(rp, relval, flags, p) get_unaligned(rp)
-#define flat_put_addr_at_rp(rp, val, relval) put_unaligned(val,rp)
+#define flat_get_addr_from_rp(rp, relval, flags, p) \
+ ({ unsigned long __val; __get_user_unaligned(__val, rp); __val; })
+#define flat_put_addr_at_rp(rp, val, relval) __put_user_unaligned(val, rp)
#define flat_get_relocate_addr(rel) (rel)
static inline int flat_set_persistent(unsigned long relval,
diff --git a/arch/sh/include/asm/flat.h b/arch/sh/include/asm/flat.h
index 5d84df5e27..0f4f49ed6b 100644
--- a/arch/sh/include/asm/flat.h
+++ b/arch/sh/include/asm/flat.h
@@ -15,8 +15,9 @@
#define flat_argvp_envp_on_stack() 0
#define flat_old_ram_flag(flags) (flags)
#define flat_reloc_valid(reloc, size) ((reloc) <= (size))
-#define flat_get_addr_from_rp(rp, relval, flags, p) get_unaligned(rp)
-#define flat_put_addr_at_rp(rp, val, relval) put_unaligned(val,rp)
+#define flat_get_addr_from_rp(rp, relval, flags, p) \
+ ({ unsigned long __val; __get_user_unaligned(__val, rp); __val; })
+#define flat_put_addr_at_rp(rp, val, relval) __put_user_unaligned(val, rp)
#define flat_get_relocate_addr(rel) (rel)
#define flat_set_persistent(relval, p) ({ (void)p; 0; })
diff --git a/arch/xtensa/include/asm/flat.h b/arch/xtensa/include/asm/flat.h
index 94c44abf15..fffad219af 100644
--- a/arch/xtensa/include/asm/flat.h
+++ b/arch/xtensa/include/asm/flat.h
@@ -4,8 +4,9 @@
#define flat_argvp_envp_on_stack() 0
#define flat_old_ram_flag(flags) (flags)
#define flat_reloc_valid(reloc, size) ((reloc) <= (size))
-#define flat_get_addr_from_rp(rp, relval, flags, p) get_unaligned(rp)
-#define flat_put_addr_at_rp(rp, val, relval ) put_unaligned(val, rp)
+#define flat_get_addr_from_rp(rp, relval, flags, p) \
+ ({ unsigned long __val; __get_user_unaligned(__val, rp); __val; })
+#define flat_put_addr_at_rp(rp, val, relval) __put_user_unaligned(val, rp)
#define flat_get_relocate_addr(rel) (rel)
#define flat_set_persistent(relval, p) 0
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 9538901fe8..fc0ee3ed5d 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -438,7 +438,7 @@ 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;
@@ -600,7 +600,7 @@ 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;
@@ -625,7 +625,7 @@ 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;
@@ -718,15 +718,20 @@ 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;
}
}
}
@@ -743,19 +748,21 @@ 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;
/* Get the address of the pointer to be
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;
}
--
2.7.4
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[PATCH 00/10] allow BFLT executables on systems with a MMU Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 07/10] binfmt_flat: use clear_user() rather than memset() to clear .bss Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 09/10] binfmt_flat: add MMU-specific support Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 03/10] binfmt_flat: use generic transfer_args_to_stack() Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 05/10] binfmt_flat: use proper user space accessors with relocs processing code Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 01/10] binfmt_flat: assorted cleanups Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 10/10] binfmt_flat: allow compressed flat binary format to work on MMU systems Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 08/10] binfmt_flat: update libraries' data segment pointer with userspace accessors Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 06/10] binfmt_flat: use proper user space accessors with old relocs code Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 02/10] elf_fdpic_transfer_args_to_stack(): make it generic Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200 [PATCH 04/10] binfmt_flat: clean up create_flat_tables() and stack accesses Nicolas Pitre <nicolas.pitre@linaro.org> - 2016-07-12 23:50 +0200
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