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debugedit: fix segment fault while file's bss offset have a large number
While ELF_C_RDWR_MMAP was used, elf_begin invoked mmap() to map file
into memory. While the file's bss Offset has a large number, elf_update
caculated file size by __elf64_updatenull_wrlock and the size was
enlarged.
In this situation, elf_update invoked ftruncate to enlarge the file,
and memory size (elf->maximum_size) also was incorrectly updated.
There was segment fault in elf_end which invoked munmap with the
length is the enlarged file size, not the mmap's length.
Before the above operations, invoke elf_begin/elf_update/elf_end
with ELF_C_RDWR and ELF_F_LAYOUT set to enlarge the above file, it
could make sure the file is safe for the following elf operations.
Upstream-Status: Submitted [RPM5 maintainer]
Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
tools/debugedit.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
Index: rpm-5.4.14/tools/debugedit.c
===================================================================
--- rpm-5.4.14.orig/tools/debugedit.c
+++ rpm-5.4.14/tools/debugedit.c
@@ -1525,6 +1525,28 @@ handle_build_id (DSO *dso, Elf_Data *bui
}
}
+/* It avoided the segment fault while file's bss offset have a large number.
+ See https://bugzilla.redhat.com/show_bug.cgi?id=1019707
+ https://bugzilla.redhat.com/show_bug.cgi?id=1020842 for detail. */
+void valid_file(int fd)
+{
+ Elf *elf = elf_begin (fd, ELF_C_RDWR, NULL);
+ if (elf == NULL)
+ {
+ error (1, 0, "elf_begin: %s", elf_errmsg (-1));
+ return;
+ }
+
+ elf_flagelf (elf, ELF_C_SET, ELF_F_LAYOUT);
+
+ if (elf_update (elf, ELF_C_WRITE) < 0)
+ error (1, 0, "elf_update: %s", elf_errmsg (-1));
+
+ elf_end (elf);
+
+ return;
+}
+
int
main (int argc, char *argv[])
{
@@ -1621,6 +1643,9 @@ main (int argc, char *argv[])
exit (1);
}
+ /* Make sure the file is valid. */
+ valid_file(fd);
+
dso = fdopen_dso (fd, file);
if (dso == NULL)
exit (1);
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