From 9fe6594da91e86280c9d71877a91cee83aaedae6 Mon Sep 17 00:00:00 2001

Message-Id: <9fe6594da91e86280c9d71877a91cee83aaedae6.1566225007.git.aquini@redhat.com>

In-Reply-To: <d42f467a923dfc09309acb7a83b42e3285fbd8f4.1566225007.git.aquini@redhat.com>

References: <d42f467a923dfc09309acb7a83b42e3285fbd8f4.1566225007.git.aquini@redhat.com>

From: Sandipan Das <sandipan@linux.ibm.com>

Date: Wed, 12 Jun 2019 12:34:30 +0530

Subject: [RHEL7 PATCH 13/31] elflink: Fix program header address calculation

This fixes the virtual address calculation for the ELF program

header. Based on the man page of dl_iterate_phdr(), the location

of a particular program header in virtual memory should be the

sum of the base address of the shared object and the segment's

virtual address.

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>

Signed-off-by: Eric B Munson <emunson@mgebm.net>

Signed-off-by: Rafael Aquini <aquini@redhat.com>

---

 elflink.c | 40 ++++++++++++++++++++++++----------------

 1 file changed, 24 insertions(+), 16 deletions(-)

diff --git a/elflink.c b/elflink.c

index ffc84dd..1150bde 100644

--- a/elflink.c

+++ b/elflink.c

@@ -374,7 +374,8 @@ static int get_shared_file_name(struct seg_info *htlb_seg_info, char *file_path)

 }

 /* Find the .dynamic program header */

-static int find_dynamic(Elf_Dyn **dyntab, const Elf_Phdr *phdr, int phnum)

+static int find_dynamic(Elf_Dyn **dyntab, const ElfW(Addr) addr,

+			const Elf_Phdr *phdr, int phnum)

 {

 	int i = 1;

@@ -382,7 +383,7 @@ static int find_dynamic(Elf_Dyn **dyntab, const Elf_Phdr *phdr, int phnum)

 		++i;

 	}

 	if (phdr[i].p_type == PT_DYNAMIC) {

-		*dyntab = (Elf_Dyn *)phdr[i].p_vaddr;

+		*dyntab = (Elf_Dyn *)(addr + phdr[i].p_vaddr);

 		return 0;

 	} else {

 		DEBUG("No dynamic segment found\n");

@@ -473,7 +474,8 @@ ElfW(Word) __attribute__ ((weak)) plt_extrasz(ElfW(Dyn) *dyntab)

  * include these initialized variables in our copy.

  */

-static void get_extracopy(struct seg_info *seg, const Elf_Phdr *phdr, int phnum)

+static void get_extracopy(struct seg_info *seg, const ElfW(Addr) addr,

+			  const Elf_Phdr *phdr, int phnum)

 {

 	Elf_Dyn *dyntab;        /* dynamic segment table */

 	Elf_Sym *symtab = NULL; /* dynamic symbol table */

@@ -492,7 +494,7 @@ static void get_extracopy(struct seg_info *seg, const Elf_Phdr *phdr, int phnum)

 		goto bail2;

 	/* Find dynamic program header */

-	ret = find_dynamic(&dyntab, phdr, phnum);

+	ret = find_dynamic(&dyntab, addr, phdr, phnum);

 	if (ret < 0)

 		goto bail;

@@ -608,7 +610,8 @@ static unsigned long hugetlb_prev_slice_end(unsigned long addr)

 /*

  * Store a copy of the given program header

  */

-static int save_phdr(int table_idx, int phnum, const ElfW(Phdr) *phdr)

+static int save_phdr(int table_idx, int phnum, const ElfW(Addr) addr,

+		     const ElfW(Phdr) *phdr)

 {

 	int prot = 0;

@@ -626,7 +629,7 @@ static int save_phdr(int table_idx, int phnum, const ElfW(Phdr) *phdr)

 	if (phdr->p_flags & PF_X)

 		prot |= PROT_EXEC;

-	htlb_seg_table[table_idx].vaddr = (void *) phdr->p_vaddr;

+	htlb_seg_table[table_idx].vaddr = (void *)(addr + phdr->p_vaddr);

 	htlb_seg_table[table_idx].filesz = phdr->p_filesz;

 	htlb_seg_table[table_idx].memsz = phdr->p_memsz;

 	htlb_seg_table[table_idx].prot = prot;

@@ -634,8 +637,8 @@ static int save_phdr(int table_idx, int phnum, const ElfW(Phdr) *phdr)

 	INFO("Segment %d (phdr %d): %#0lx-%#0lx  (filesz=%#0lx) "

 		"(prot = %#0x)\n", table_idx, phnum,

-		(unsigned long)  phdr->p_vaddr,

-		(unsigned long) phdr->p_vaddr + phdr->p_memsz,

+		(unsigned long) addr + phdr->p_vaddr,

+		(unsigned long) addr + phdr->p_vaddr + phdr->p_memsz,

 		(unsigned long) phdr->p_filesz, (unsigned int) prot);

 	return 0;

@@ -718,16 +721,19 @@ int parse_elf_normal(struct dl_phdr_info *info, size_t size, void *data)

 		seg_psize = segment_requested_page_size(&info->dlpi_phdr[i]);

 		if (seg_psize != page_size) {

-			if (save_phdr(htlb_num_segs, i, &info->dlpi_phdr[i]))

+			if (save_phdr(htlb_num_segs, i, info->dlpi_addr,

+				      &info->dlpi_phdr[i]))

 				return 1;

 			get_extracopy(&htlb_seg_table[htlb_num_segs],

-					&info->dlpi_phdr[0], info->dlpi_phnum);

+				      info->dlpi_addr, info->dlpi_phdr,

+				      info->dlpi_phnum);

 			htlb_seg_table[htlb_num_segs].page_size = seg_psize;

 			htlb_num_segs++;

 		}

-		start = ALIGN_DOWN(info->dlpi_phdr[i].p_vaddr, seg_psize);

-		end = ALIGN(info->dlpi_phdr[i].p_vaddr +

-				info->dlpi_phdr[i].p_memsz, seg_psize);

+		start = ALIGN_DOWN(info->dlpi_addr +

+				   info->dlpi_phdr[i].p_vaddr, seg_psize);

+		end = ALIGN(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr +

+			    info->dlpi_phdr[i].p_memsz, seg_psize);

 		segments[num_segs].page_size = seg_psize;

 		segments[num_segs].start = start;

@@ -771,8 +777,9 @@ int parse_elf_partial(struct dl_phdr_info *info, size_t size, void *data)

 		 * in this forced way won't violate any contiguity

 		 * constraints.

 		 */

-		vaddr = hugetlb_next_slice_start(info->dlpi_phdr[i].p_vaddr);

-		gap = vaddr - info->dlpi_phdr[i].p_vaddr;

+		vaddr = hugetlb_next_slice_start(info->dlpi_addr +

+						 info->dlpi_phdr[i].p_vaddr);

+		gap = vaddr - (info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);

 		slice_end = hugetlb_slice_end(vaddr);

 		/*

 		 * we should stop remapping just before the slice

@@ -795,7 +802,8 @@ int parse_elf_partial(struct dl_phdr_info *info, size_t size, void *data)

 		}

 		memsz = hugetlb_prev_slice_end(vaddr + memsz) - vaddr;

-		if (save_phdr(htlb_num_segs, i, &info->dlpi_phdr[i]))

+		if (save_phdr(htlb_num_segs, i, info->dlpi_addr,

+			      &info->dlpi_phdr[i]))

 			return 1;

 		/*

-- 

1.8.3.1