From: Mark Wielaard <mark@klomp.org>
Date: Fri, 17 Dec 2021 16:43:19 +0000 (+0100)
Subject: libdwfl: Make dwfl_segment_report_module aware of maximum Elf size
X-Git-Tag: elfutils-0.187~55
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3831c0b2c2334b129a9d04f12dc7549db412d3bd;p=thirdparty%2Felfutils.git

libdwfl: Make dwfl_segment_report_module aware of maximum Elf size

At the end of dwfl_segment_report_module we might try to read in
the whole contents described by a core file. To do this we first
allocate a zeroed block of memory that is as big as possible. The
core file however may describe much more loaded data than is actually
available in the Elf image. So pass the maximum size so we can
limit the amount of memory we reserve.

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

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index f18a0c457..6a3e041bd 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,11 @@
+2021-12-17  Mark Wielaard  <mark@klomp.org>
+
+	* libdwflP.h (dwfl_segment_report_module): Add maxread argument.
+	* core-file.c (dwfl_core_file_report): Pass elf->maximum_size to
+	dwfl_segment_report_module.
+	* dwfl_segment_report_module.c (dwfl_segment_report_module): Add
+	maxread argument. Check file_trimmed_end against maxread.
+
 2021-12-16  Mark Wielaard  <mark@klomp.org>
 
 	* dwfl_segment_report_module.c (dwfl_segment_report_module): Check
diff --git a/libdwfl/core-file.c b/libdwfl/core-file.c
index 4e4c9b3cf..b04d1d18b 100644
--- a/libdwfl/core-file.c
+++ b/libdwfl/core-file.c
@@ -559,6 +559,7 @@ dwfl_core_file_report (Dwfl *dwfl, Elf *elf, const char *executable)
       int seg = dwfl_segment_report_module (dwfl, ndx, NULL,
 					    &dwfl_elf_phdr_memory_callback, elf,
 					    core_file_read_eagerly, elf,
+					    elf->maximum_size,
 					    note_file, note_file_size,
 					    &r_debug_info);
       if (unlikely (seg < 0))
diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c
index 2263e3cc1..3e87d2070 100644
--- a/libdwfl/dwfl_segment_report_module.c
+++ b/libdwfl/dwfl_segment_report_module.c
@@ -294,6 +294,7 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
 			    void *memory_callback_arg,
 			    Dwfl_Module_Callback *read_eagerly,
 			    void *read_eagerly_arg,
+			    size_t maxread,
 			    const void *note_file, size_t note_file_size,
 			    const struct r_debug_info *r_debug_info)
 {
@@ -911,8 +912,8 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
       /* The caller wants to read the whole file in right now, but hasn't
 	 done it for us.  Fill in a local image of the virtual file.  */
 
-      if (file_trimmed_end > SIZE_MAX)
-	goto out;
+      if (file_trimmed_end > maxread)
+	file_trimmed_end = maxread;
 
       void *contents = calloc (1, file_trimmed_end);
       if (unlikely (contents == NULL))
diff --git a/libdwfl/libdwflP.h b/libdwfl/libdwflP.h
index 4344e356b..7503a6273 100644
--- a/libdwfl/libdwflP.h
+++ b/libdwfl/libdwflP.h
@@ -698,6 +698,7 @@ extern int dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
 				       void *memory_callback_arg,
 				       Dwfl_Module_Callback *read_eagerly,
 				       void *read_eagerly_arg,
+				       size_t maxread,
 				       const void *note_file,
 				       size_t note_file_size,
 				       const struct r_debug_info *r_debug_info);