https://sourceware.org/bugzilla/show_bug.cgi?id=32896
--- Comment #5 from Matthew Malcomson <mmalcomson at nvidia dot com> --- I think that this proposed patch could allow putting the PT_TLS segment offset past the end of the file (that I think was a problem in https://sourceware.org/bugzilla/show_bug.cgi?id=12921 ). This because it doesn't adjust the `off` that indicates position into the file. Very artificial testcase below showing this as a possibility (with the proposed patch applied). vshcmd: > cat tbss-outside-file.s # Testcase to stress-test the patch that H. J. Lu suggested. .section .gcc_except_table,"aw",@progbits .align 4 .ascii "Odd number of chars" .section .tbss,"awT",@nobits .align 10 .type abc, @object .size abc, 4 abc: .zero 4 .text .global _start _start: tls-segfault [11:33:10] $ vshcmd: > ../build-aarch64-none-linux-gnu/install/bin/aarch64-none-linux-gnu-as \ vshcmd: > tbss-outside-file.s -o tbss-outside-file.o vshcmd: > ../build-aarch64-none-linux-gnu/install/bin/aarch64-none-linux-gnu-ld \ vshcmd: > tbss-outside-file.o -o tbss-outside-file vshcmd: > ../build-aarch64-none-linux-gnu/install/bin/aarch64-none-linux-gnu-readelf --segments --wide tbss-outside-file \ vshcmd: > | grep -E '(^Program|VirtAddr|TLS)' vshcmd: > ../build-aarch64-none-linux-gnu/install/bin/aarch64-none-linux-gnu-readelf --segments --wide tbss-outside-file > tls-segfault [11:33:18] $ > tls-segfault [11:33:18] $ > Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align TLS 0x010400 0x0000000000410400 0x0000000000410400 0x000000 0x000004 R 0x400 tls-segfault [11:33:18] $ Elf file type is EXEC (Executable file) Entry point 0x4000e8 There are 3 program headers, starting at offset 64 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align LOAD 0x000000 0x0000000000400000 0x0000000000400000 0x010013 0x010013 RW 0x10000 TLS 0x010400 0x0000000000410400 0x0000000000410400 0x000000 0x000004 R 0x400 GNU_RELRO 0x010000 0x0000000000410000 0x0000000000410000 0x000013 0x010000 R 0x1 Section to Segment mapping: Segment Sections... 00 .gcc_except_table 01 .tbss 02 .gcc_except_table tls-segfault [11:33:18] $ vshcmd: > # Seems like this could trigger the same problem as was seen in issue vshcmd: > # 12921 https://sourceware.org/bugzilla/show_bug.cgi?id=12921#c6 vshcmd: > du --bytes tbss-outside-file \ vshcmd: > | python3 -c 'import sys; a = sys.stdin.readline().split(); print(hex(int(a[0])), a[1])' > 0x103d0 tbss-outside-file tls-segfault [11:33:20] $ -- You are receiving this mail because: You are on the CC list for the bug.
