Allocate exact amount of bytes for phdrs and shdrs.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

4 files changed, 48 insertions, 42 deletions

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 949a3728..ee41405e 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,13 @@
+2015-10-07  Mark Wielaard  <mjw@redhat.com>
+
+	* dwfl_module_getdwarf.c (MAX): Removed.
+	(find_prelink_address_sync): Allocate exact amount of bytes for
+	phdrs and shdrs.
+	* dwfl_segment_report_module.c (dwfl_segment_report_module):
+	Likewise for phdrs.
+	* elf-from-memory.c (MAX): Removed.
+	(elf_from_remote_memory): Allocate exact amount of bytes for phdrs.
+
 2015-10-05  Chih-Hung Hsieh <chh@google.com>
 
 	* dwfl_module_getdwarf.c (find_prelink_address_sync): Do not use
diff --git a/libdwfl/dwfl_module_getdwarf.c b/libdwfl/dwfl_module_getdwarf.c
index c339040e..a3590577 100644
--- a/libdwfl/dwfl_module_getdwarf.c
+++ b/libdwfl/dwfl_module_getdwarf.c
@@ -34,10 +34,6 @@
 #include "../libdw/libdwP.h"	/* DWARF_E_* values are here.  */
 #include "../libelf/libelfP.h"
 
-#ifndef MAX
-# define MAX(a, b) ((a) > (b) ? (a) : (b))
-#endif
-
 static inline Dwfl_Error
 open_elf_file (Elf **elf, int *fd, char **name)
 {
@@ -371,15 +367,13 @@ find_prelink_address_sync (Dwfl_Module *mod, struct dwfl_file *file)
   src.d_size = phnum * phentsize;
 
   GElf_Addr undo_interp = 0;
+  bool class32 = ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32;
   {
-    if (unlikely (phnum >
-                  SIZE_MAX / MAX (sizeof (Elf32_Phdr), sizeof (Elf64_Phdr))))
+    size_t phdr_size = class32 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr);
+    if (unlikely (phnum > SIZE_MAX / phdr_size))
       return DWFL_E_NOMEM;
-    const size_t phdrs_bytes =
-        phnum * MAX (sizeof (Elf32_Phdr), sizeof (Elf64_Phdr));
+    const size_t phdrs_bytes = phnum * phdr_size;
     void *phdrs = malloc (phdrs_bytes);
-    Elf32_Phdr (*p32)[phnum] = phdrs;
-    Elf64_Phdr (*p64)[phnum] = phdrs;
     if (unlikely (phdrs == NULL))
       return DWFL_E_NOMEM;
     dst.d_buf = phdrs;
@@ -390,8 +384,9 @@ find_prelink_address_sync (Dwfl_Module *mod, struct dwfl_file *file)
 	free (phdrs);
 	return DWFL_E_LIBELF;
       }
-    if (ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32)
+    if (class32)
       {
+	Elf32_Phdr (*p32)[phnum] = phdrs;
 	for (uint_fast16_t i = 0; i < phnum; ++i)
 	  if ((*p32)[i].p_type == PT_INTERP)
 	    {
@@ -401,6 +396,7 @@ find_prelink_address_sync (Dwfl_Module *mod, struct dwfl_file *file)
       }
     else
       {
+	Elf64_Phdr (*p64)[phnum] = phdrs;
 	for (uint_fast16_t i = 0; i < phnum; ++i)
 	  if ((*p64)[i].p_type == PT_INTERP)
 	    {
@@ -418,14 +414,11 @@ find_prelink_address_sync (Dwfl_Module *mod, struct dwfl_file *file)
   src.d_type = ELF_T_SHDR;
   src.d_size = gelf_fsize (mod->main.elf, ELF_T_SHDR, shnum - 1, EV_CURRENT);
 
-  if (unlikely (shnum - 1  >
-                SIZE_MAX / MAX (sizeof (Elf32_Shdr), sizeof (Elf64_Shdr))))
+  size_t shdr_size = class32 ? sizeof (Elf32_Shdr) : sizeof (Elf64_Shdr);
+  if (unlikely (shnum - 1  > SIZE_MAX / shdr_size))
     return DWFL_E_NOMEM;
-  const size_t shdrs_bytes =
-      (shnum - 1) * MAX (sizeof (Elf32_Shdr), sizeof (Elf64_Shdr));
+  const size_t shdrs_bytes = (shnum - 1) * shdr_size;
   void *shdrs = malloc (shdrs_bytes);
-  Elf32_Shdr (*s32)[shnum - 1] = shdrs;
-  Elf64_Shdr (*s64)[shnum - 1] = shdrs;
   if (unlikely (shdrs == NULL))
     return DWFL_E_NOMEM;
   dst.d_buf = shdrs;
@@ -490,16 +483,22 @@ find_prelink_address_sync (Dwfl_Module *mod, struct dwfl_file *file)
       mod->main.address_sync = highest;
 
       highest = 0;
-      if (ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32)
-	for (size_t i = 0; i < shnum - 1; ++i)
-	  consider_shdr (undo_interp, (*s32)[i].sh_type,
-			 (*s32)[i].sh_flags, (*s32)[i].sh_addr,
-			 (*s32)[i].sh_size);
+      if (class32)
+	{
+	  Elf32_Shdr (*s32)[shnum - 1] = shdrs;
+	  for (size_t i = 0; i < shnum - 1; ++i)
+	    consider_shdr (undo_interp, (*s32)[i].sh_type,
+			   (*s32)[i].sh_flags, (*s32)[i].sh_addr,
+			   (*s32)[i].sh_size);
+	}
       else
-	for (size_t i = 0; i < shnum - 1; ++i)
-	  consider_shdr (undo_interp, (*s64)[i].sh_type,
-			 (*s64)[i].sh_flags, (*s64)[i].sh_addr,
-			 (*s64)[i].sh_size);
+	{
+	  Elf64_Shdr (*s64)[shnum - 1] = shdrs;
+	  for (size_t i = 0; i < shnum - 1; ++i)
+	    consider_shdr (undo_interp, (*s64)[i].sh_type,
+			   (*s64)[i].sh_flags, (*s64)[i].sh_addr,
+			   (*s64)[i].sh_size);
+	}
 
       if (highest > file->vaddr)
 	file->address_sync = highest;
diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c
index 92f691d8..ca86c311 100644
--- a/libdwfl/dwfl_segment_report_module.c
+++ b/libdwfl/dwfl_segment_report_module.c
@@ -408,14 +408,12 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
 
   xlatefrom.d_buf = ph_buffer;
 
-  if (unlikely (phnum >
-                SIZE_MAX / MAX (sizeof (Elf32_Phdr), sizeof (Elf64_Phdr))))
+  bool class32 = ei_class == ELFCLASS32;
+  size_t phdr_size = class32 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr);
+  if (unlikely (phnum > SIZE_MAX / phdr_size))
     return finish ();
-  const size_t phdrsp_bytes =
-      phnum * MAX (sizeof (Elf32_Phdr), sizeof (Elf64_Phdr));
+  const size_t phdrsp_bytes = phnum * phdr_size;
   phdrsp = malloc (phdrsp_bytes);
-  Elf32_Phdr (*p32)[phnum] = phdrsp;
-  Elf64_Phdr (*p64)[phnum] = phdrsp;
   if (unlikely (phdrsp == NULL))
     return finish ();
 
@@ -577,6 +575,9 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
 	break;
       }
   }
+
+  Elf32_Phdr (*p32)[phnum] = phdrsp;
+  Elf64_Phdr (*p64)[phnum] = phdrsp;
   if (ei_class == ELFCLASS32)
     {
       if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
diff --git a/libdwfl/elf-from-memory.c b/libdwfl/elf-from-memory.c
index 5be21bb0..dd42e954 100644
--- a/libdwfl/elf-from-memory.c
+++ b/libdwfl/elf-from-memory.c
@@ -38,10 +38,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-#ifndef MAX
-# define MAX(a, b) ((a) > (b) ? (a) : (b))
-#endif
-
 /* Reconstruct an ELF file by reading the segments out of remote memory
    based on the ELF file header at EHDR_VMA and the ELF program headers it
    points to.  If not null, *LOADBASEP is filled in with the difference
@@ -195,17 +191,15 @@ elf_from_remote_memory (GElf_Addr ehdr_vma,
       xlatefrom.d_buf = buffer;
     }
 
-  if (unlikely (phnum >
-                SIZE_MAX / MAX (sizeof (Elf32_Phdr), sizeof (Elf64_Phdr))))
+  bool class32 = ehdr.e32.e_ident[EI_CLASS] == ELFCLASS32;
+  size_t phdr_size = class32 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr);
+  if (unlikely (phnum > SIZE_MAX / phdr_size))
     {
       free (buffer);
       goto no_memory;
     }
-  const size_t phdrsp_bytes =
-      phnum * MAX (sizeof (Elf32_Phdr), sizeof (Elf64_Phdr));
+  const size_t phdrsp_bytes = phnum * phdr_size;
   phdrsp = malloc (phdrsp_bytes);
-  Elf32_Phdr (*p32)[phnum] = phdrsp;
-  Elf64_Phdr (*p64)[phnum] = phdrsp;
   if (unlikely (phdrsp == NULL))
     {
       free (buffer);
@@ -221,6 +215,8 @@ elf_from_remote_memory (GElf_Addr ehdr_vma,
   GElf_Off segments_end_mem = 0;
   GElf_Addr loadbase = ehdr_vma;
   bool found_base = false;
+  Elf32_Phdr (*p32)[phnum] = phdrsp;
+  Elf64_Phdr (*p64)[phnum] = phdrsp;
   switch (ehdr.e32.e_ident[EI_CLASS])
     {
       /* Sanity checks segments and calculates segment_end,