Merge branch 'fdpic' of http://git.linaro.org/people/nicolas.pitre/linux into devel-stable

This series provides the needed changes to suport the ELF_FDPIC binary
format on ARM. Both MMU and non-MMU systems are supported. This format
has many advantages over the BFLT format used on MMU-less systems, such
as being real ELF that can be parsed by standard tools, can support
shared dynamic libs, etc.

3 files changed, 26 insertions, 6 deletions

diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index b2f82cf6bf86..58c2bbd385ad 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -34,8 +34,8 @@ config ARCH_BINFMT_ELF_STATE
 
 config BINFMT_ELF_FDPIC
 	bool "Kernel support for FDPIC ELF binaries"
-	default y
-	depends on (FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)
+	default y if !BINFMT_ELF
+	depends on (ARM || FRV || BLACKFIN || (SUPERH32 && !MMU) || C6X)
 	select ELFCORE
 	help
 	  ELF FDPIC binaries are based on ELF, but allow the individual load
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 73b01e474fdc..e4f7ef8294ac 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -51,6 +51,11 @@
 #define user_siginfo_t siginfo_t
 #endif
 
+/* That's for binfmt_elf_fdpic to deal with */
+#ifndef elf_check_fdpic
+#define elf_check_fdpic(ex) false
+#endif
+
 static int load_elf_binary(struct linux_binprm *bprm);
 static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
 				int, int, unsigned long);
@@ -541,7 +546,8 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 	if (interp_elf_ex->e_type != ET_EXEC &&
 	    interp_elf_ex->e_type != ET_DYN)
 		goto out;
-	if (!elf_check_arch(interp_elf_ex))
+	if (!elf_check_arch(interp_elf_ex) ||
+	    elf_check_fdpic(interp_elf_ex))
 		goto out;
 	if (!interpreter->f_op->mmap)
 		goto out;
@@ -718,6 +724,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		goto out;
 	if (!elf_check_arch(&loc->elf_ex))
 		goto out;
+	if (elf_check_fdpic(&loc->elf_ex))
+		goto out;
 	if (!bprm->file->f_op->mmap)
 		goto out;
 
@@ -817,7 +825,8 @@ static int load_elf_binary(struct linux_binprm *bprm)
 		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 			goto out_free_dentry;
 		/* Verify the interpreter has a valid arch */
-		if (!elf_check_arch(&loc->interp_elf_ex))
+		if (!elf_check_arch(&loc->interp_elf_ex) ||
+		    elf_check_fdpic(&loc->interp_elf_ex))
 			goto out_free_dentry;
 
 		/* Load the interpreter program headers */
@@ -1190,6 +1199,8 @@ static int load_elf_library(struct file *file)
 	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
 	    !elf_check_arch(&elf_ex) || !file->f_op->mmap)
 		goto out;
+	if (elf_check_fdpic(&elf_ex))
+		goto out;
 
 	/* Now read in all of the header information */
 
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index e70c039ac190..5429b035e249 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -378,6 +378,11 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm)
 				 executable_stack);
 	if (retval < 0)
 		goto error;
+#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
+	retval = arch_setup_additional_pages(bprm, !!interpreter_name);
+	if (retval < 0)
+		goto error;
+#endif
 #endif
 
 	/* load the executable and interpreter into memory */
@@ -831,6 +836,9 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 			if (phdr->p_vaddr >= seg->p_vaddr &&
 			    phdr->p_vaddr + phdr->p_memsz <=
 			    seg->p_vaddr + seg->p_memsz) {
+				Elf32_Dyn __user *dyn;
+				Elf32_Sword d_tag;
+
 				params->dynamic_addr =
 					(phdr->p_vaddr - seg->p_vaddr) +
 					seg->addr;
@@ -843,8 +851,9 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
 					goto dynamic_error;
 
 				tmp = phdr->p_memsz / sizeof(Elf32_Dyn);
-				if (((Elf32_Dyn *)
-				     params->dynamic_addr)[tmp - 1].d_tag != 0)
+				dyn = (Elf32_Dyn __user *)params->dynamic_addr;
+				__get_user(d_tag, &dyn[tmp - 1].d_tag);
+				if (d_tag != 0)
 					goto dynamic_error;
 				break;
 			}