https://sourceware.org/bugzilla/show_bug.cgi?id=24156
Bug ID: 24156
Summary: gcc -N -nostdlib test.c creates PT_PHDR out of range
for auxiliary vector fetching of AT_PHDR
Product: binutils
Version: 2.31
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: ld
Assignee: unassigned at sourceware dot org
Reporter: ryan at bitlackeys dot org
Target Milestone: ---
In older versions such as 2.24 this wasn't a problem because it did not
include an INTERP segment, therefore no auxv fetching was necessary. In newer
versions the ld-linux.so fails to find AT_PHDR on the auxv (On the stack)
because it PT_PHDR exists outside of a LOAD segment-- and lastly, the original
behavior of -N -nostdlib never included a PT_INTERP segment. Although I agree
that -N -nostdlib -static is more correct for excluding an interpreter. Still
if PT_INTERP is going to exist, the interpreter will need a valid AT_PHDR,
otherwise the program segfaults.
elfmaster@dreamcity:~/git/scop_virus$ ld -v
GNU ld (GNU Binutils for Ubuntu) 2.30
elfmaster@dreamcity:~/git/scop_virus$
elfmaster@dreamcity:~/git/scop_virus$ gcc -N -nostdlib t.c -o t
elfmaster@dreamcity:~/git/scop_virus$ readelf -l t
Elf file type is EXEC (Executable file)
Entry point 0x400241
There are 7 program headers, starting at offset 64
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
PHDR 0x0000000000000040 0x0000000000200040 0x0000000000000000
0x0000000000000188 0x0000000000000188 R 0x8
readelf: Error: the PHDR segment is not covered by a LOAD segment
INTERP 0x00000000000001c8 0x00000000004001c8 0x00000000004001c8
0x000000000000001c 0x000000000000001c R 0x1
[Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]
LOAD 0x00000000000001c8 0x00000000004001c8 0x00000000004001c8
0x00000000000001b0 0x00000000000001b0 RWE 0x8
DYNAMIC 0x0000000000000298 0x0000000000400298 0x0000000000400298
0x00000000000000e0 0x00000000000000e0 RW 0x8
NOTE 0x00000000000001e4 0x00000000004001e4 0x00000000004001e4
0x0000000000000024 0x0000000000000024 R 0x4
GNU_EH_FRAME 0x0000000000000248 0x0000000000400248 0x0000000000400248
0x0000000000000014 0x0000000000000014 R 0x4
GNU_STACK 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x0000000000000000 0x0000000000000000 RW 0x10
Section to Segment mapping:
Segment Sections...
00
01 .interp
02 .interp .note.gnu.build-id .gnu.hash .dynsym .dynstr .text
.eh_frame_hdr .eh_frame .dynamic
03 .dynamic
04 .note.gnu.build-id
05 .eh_frame_hdr
06
elfmaster@dreamcity:~/git/scop_virus$ LD_SHOW_AUXV=1 ./t
AT_SYSINFO_EHDR: 0x7ffeaa5ba000
AT_HWCAP: bfebfbff
AT_PAGESZ: 4096
AT_CLKTCK: 100
AT_PHDR: 0x400040
AT_PHENT: 56
AT_PHNUM: 7
AT_BASE: 0x7f7d95c61000
AT_FLAGS: 0x0
AT_ENTRY: 0x400241
AT_UID: 1000
AT_EUID: 1000
AT_GID: 1000
AT_EGID: 1000
AT_SECURE: 0
AT_RANDOM: 0x7ffeaa4eecd9
AT_HWCAP2: 0x0
AT_EXECFN: ./t
AT_PLATFORM: x86_64
Segmentation fault (core dumped)
elfmaster@dreamcity:~/git/scop_virus$
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