Package: glibc / 2.24-11+deb9u4

arm/unsubmitted-ldso-abi-check.diff Patch series | download
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---
 elf/dl-load.c |  218 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 218 insertions(+)

--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -1644,6 +1644,209 @@
     _dl_debug_printf_c ("\t\t(%s)\n", what);
 }
 
+#ifdef __arm__
+/* Read an unsigned leb128 value from P, store the value in VAL, return
+   P incremented past the value.  We assume that a word is large enough to
+   hold any value so encoded; if it is smaller than a pointer on some target,
+   pointers should not be leb128 encoded on that target.  */
+static unsigned char *
+read_uleb128 (unsigned char *p, unsigned long *val)
+{
+  unsigned int shift = 0;
+  unsigned char byte;
+  unsigned long result;
+
+  result = 0;
+  do
+    {
+      byte = *p++;
+      result |= (byte & 0x7f) << shift;
+      shift += 7;
+    }
+  while (byte & 0x80);
+
+  *val = result;
+  return p;
+}
+
+
+#define ATTR_TAG_FILE          1
+#define ABI_VFP_args          28
+#define VFP_ARGS_IN_VFP_REGS   1
+
+/* Check consistency of ABI in the ARM attributes. Search through the
+   section headers looking for the ARM attributes section, then
+   check the VFP_ARGS attribute. */
+static int
+check_arm_attributes_hfabi(int fd, ElfW(Ehdr) *ehdr, bool *is_hf)
+{
+  unsigned int i;
+  ElfW(Shdr) *shdrs;
+  int sh_size = ehdr->e_shentsize * ehdr->e_shnum;
+
+  /* Load in the section headers so we can look for the attributes
+   * section */
+  shdrs = alloca(sh_size);
+  __lseek (fd, ehdr->e_shoff, SEEK_SET);
+  if ((size_t) __libc_read (fd, (void *) shdrs, sh_size) != sh_size)
+    return -1;
+
+  for (i = 0; i < ehdr->e_shnum; i++)
+    {
+      if (SHT_ARM_ATTRIBUTES == shdrs[i].sh_type)
+        {
+	  /* We've found a likely section. Load the contents and
+	   * check the tags */
+	  unsigned char *contents = alloca(shdrs[i].sh_size);
+	  unsigned char *p = contents;
+	  unsigned char * end;
+
+	  __lseek (fd, shdrs[i].sh_offset, SEEK_SET);
+	  if ((size_t) __libc_read (fd, (void *) contents, shdrs[i].sh_size) != shdrs[i].sh_size)
+	    return -1;
+
+	  /* Sanity-check the attribute section details. Make sure
+	   * that it's the "aeabi" section, that's all we care
+	   * about. */
+	  if (*p == 'A')
+            {
+	      unsigned long len = shdrs[i].sh_size - 1;
+	      unsigned long namelen;
+	      p++;
+
+	      while (len > 0)
+                {
+		  unsigned long section_len = p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;
+		  if (section_len > len)
+                    {
+		      _dl_debug_printf_c ("    invalid section len %lu, max remaining %lu\n", section_len, len);
+		      section_len = len;
+                    }
+
+		  p += 4;
+		  len -= section_len;
+		  section_len -= 4;
+
+		  if (0 != strcmp((char *)p, "aeabi"))
+                    {
+		      _dl_debug_printf_c ("    ignoring unknown attr section %s\n", p);
+		      p += section_len;
+		      continue;
+                    }
+		  namelen = strlen((char *)p) + 1;
+		  p += namelen;
+		  section_len -= namelen;
+
+		  /* We're in a valid section. Walk through this
+		   * section looking for the tag we care about
+		   * (ABI_VFP_args) */
+		  while (section_len > 0)
+                    {
+		      unsigned long val = 0;
+		      unsigned long tag;
+		      unsigned long size;
+
+		      end = p;
+		      tag = (*p++);
+
+		      size = p[0] | p[1] << 8 | p[2] << 16 | p[3] << 24;
+		      if (size > section_len)
+                        {
+			  _dl_debug_printf_c ("    invalid subsection length %lu, max allowed %lu\n", size, section_len);
+			  size = section_len;
+                        }
+		      p += 4;
+
+		      section_len -= size;
+		      end += size;
+		      if (ATTR_TAG_FILE != tag)
+                        {
+			  /* ignore, we don't care */
+			  _dl_debug_printf_c ("    ignoring unknown subsection with type %lu length %lu\n", tag, size);
+			  p = end;
+			  continue;
+                        }
+		      while (p < end)
+                        {
+			  p = read_uleb128 (p, &tag);
+			  /* Handle the different types of tag. */
+			  if ( (tag == 4) || (tag == 5) || (tag == 67) )
+                            {
+			      /* Special cases for string values */
+			      namelen = strlen((char *)p) + 1;
+			      p += namelen;
+                            }
+			  else
+                            {
+			      p = read_uleb128 (p, &val);
+                            }
+			  if ( (tag == ABI_VFP_args) && (val == VFP_ARGS_IN_VFP_REGS) )
+                            {
+			      *is_hf = 1;
+			      return 0;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+  return 0;
+}
+
+
+/* ARM-specific checks. If we're built using the HF ABI, then fail any
+   attempts to use the SF ABI (and vice versa). Then, check for
+   consistency of ABI in terms of passing VFP args. */
+static int
+arm_specific_checks(int fd, const char *name, ElfW(Ehdr) *ehdr)
+{
+  static int all_hf = -1; /* unset */
+  bool is_hf = false;
+  int ret;
+
+  ret = check_arm_attributes_hfabi(fd, ehdr, &is_hf);
+  if (ret != 0)
+    return ret;
+
+#ifdef __ARM_PCS_VFP
+  if (!is_hf)
+    return EINVAL;
+#else
+  if (is_hf)
+    return EINVAL;
+#endif
+
+  if (all_hf == -1)
+    {
+      if (is_hf)
+	all_hf = 1;
+      else
+	all_hf = 0;
+    }
+  else if (all_hf == 1 && !is_hf)
+    return EINVAL;
+  else if (all_hf == 0 && is_hf)
+    return EINVAL;
+  return 0;
+}
+#endif
+
+
+/* Run any architecture-specific checks that might be needed for the
+   current architecture. */
+static int
+arch_specific_checks(int fd, const char *name, ElfW(Ehdr) *ehdr)
+{
+#ifdef __arm__
+    return arm_specific_checks(fd, name, ehdr);
+#endif
+
+  return 0;
+}
+
+
 /* Open a file and verify it is an ELF file for this architecture.  We
    ignore only ELF files for other architectures.  Non-ELF files and
    ELF files with different header information cause fatal errors since
@@ -1842,6 +2044,7 @@
 
       /* Check .note.ABI-tag if present.  */
       for (ph = phdr; ph < &phdr[ehdr->e_phnum]; ++ph)
+      {
 	if (ph->p_type == PT_NOTE && ph->p_filesz >= 32 && ph->p_align >= 4)
 	  {
 	    ElfW(Addr) size = ph->p_filesz;
@@ -1890,6 +2093,21 @@
 	    break;
 	  }
     }
+      if (-1 != fd)
+	{
+	  int error = arch_specific_checks(fd, name, ehdr);
+	  if (EINVAL == error)
+	    {
+	      goto close_and_out;
+	    }
+	  if (0 != error)
+	    {
+	      errstring = N_("Unable to run arch-specific checks\n");
+	      goto call_lose;
+	    }
+	}
+
+    }
 
   return fd;
 }