From: Mark Wielaard <mark@klomp.org>
Date: Fri, 24 Dec 2021 00:44:57 +0000 (+0100)
Subject: libdwfl: Call xlatetom on aligned buffers in dwfl_link_map_report
X-Git-Tag: elfutils-0.187~44
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5b490793e2ab651df6bbf87f3a06e2552f48be81;p=platform%2Fupstream%2Felfutils.git

libdwfl: Call xlatetom on aligned buffers in dwfl_link_map_report

Make sure that when calling xlatetom for Phdrs and Dyns in
dwfl_link_map_report the input buffer is correctly aligned by calling
memcpy and setting in.d_buf to out.d_buf.

https://sourceware.org/bugzilla/show_bug.cgi?id=28720

Signed-off-by: Mark Wielaard <mark@klomp.org>
---

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 49a35e4..73d8613 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,5 +1,10 @@
 2021-12-23  Mark Wielaard  <mark@klomp.org>
 
+	* link_map.c (dwfl_link_map_report): Call memcpy and set in.d_buf to
+	out.d_buf before calling xlatetom for unaligned buffers.
+
+2021-12-23  Mark Wielaard  <mark@klomp.org>
+
 	* core-file.c (dwfl_elf_phdr_memory_callback): Check start <
 	elf->maximum_size and end - start < minread.
 
diff --git a/libdwfl/link_map.c b/libdwfl/link_map.c
index c4f79f1..f57c558 100644
--- a/libdwfl/link_map.c
+++ b/libdwfl/link_map.c
@@ -922,11 +922,20 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size,
 		      return false;
 		    }
 		}
+	      bool is32 = (elfclass == ELFCLASS32);
+	      size_t phdr_align = (is32
+				   ? __alignof__ (Elf32_Phdr)
+				   : __alignof__ (Elf64_Phdr));
+	      if (!in_from_exec
+		  && ((uintptr_t) in.d_buf & (phdr_align - 1)) != 0)
+		{
+		  memcpy (out.d_buf, in.d_buf, in.d_size);
+		  in.d_buf = out.d_buf;
+		}
 	      if (likely ((elfclass == ELFCLASS32
 			   ? elf32_xlatetom : elf64_xlatetom)
 			  (&out, &in, elfdata) != NULL))
 		{
-		  bool is32 = (elfclass == ELFCLASS32);
 		  for (size_t i = 0; i < phnum; ++i)
 		    {
 		      GElf_Word type = (is32
@@ -1044,6 +1053,14 @@ dwfl_link_map_report (Dwfl *dwfl, const void *auxv, size_t auxv_size,
 		};
 	      if (in.d_size > out.d_size)
 		in.d_size = out.d_size;
+	      size_t dyn_align = (elfclass == ELFCLASS32
+			          ? __alignof__ (Elf32_Dyn)
+				  : __alignof__ (Elf64_Dyn));
+	      if (((uintptr_t) in.d_buf & (dyn_align - 1)) != 0)
+		{
+		  memcpy (out.d_buf, in.d_buf, in.d_size);
+		  in.d_buf = out.d_buf;
+		}
 	      if (likely ((elfclass == ELFCLASS32
 			   ? elf32_xlatetom : elf64_xlatetom)
 			  (&out, &in, elfdata) != NULL))