In kernel 2.4.3 and 2.2.18, there is a bug in fs/binfmt_elf.c function load_elf_binary(). An ET_DYN file that asks for a PT_INTERP, and whose first PT_LOAD is not at 0, gets AT_PHDR that is (load_bias + 2 * p_vaddr), instead of the correct (load_bias + p_vaddr). The patch for 2.4.3 is --- fs/OLDbinfmt_elf.c Mon Mar 19 17:05:16 2001 +++ fs/binfmt_elf.c Sat Jun 2 16:20:54 2001 @@ -632,5 +632,5 @@ load_bias += error - ELF_PAGESTART(load_bias + vaddr); - load_addr += error; + load_addr += load_bias; } } ===== Please cc: me if appropriate; I'm not subscribed. To demonstrate the problem on i386: cat >foo.s <<EOF .section ".interp" .asciz "/tmp/ld-linux.so.2" .text _start: .weak _start main: .weak main foo: jmp foo EOF gcc -nostartfiles -o foo.so foo.s # Now, binary edit foo.so to change Elf32_Ehdr.e_type from ET_EXEC to ET_DYN. # The 'short' at file offset 0x10 goes from 2 to 3. cp /lib/ld-linux.so.2 /tmp # Now, binary edit /tmp/ld-linux.so.2 so that it begins with an infinite loop. # "objdump -f" gives the entry address. (short)0xfeeb is an infinite loop. nice ldd foo.so & # Here is the failure. Start in background at low priority. cat /proc/<pid_of_foo.so>/maps # I see pid_of_foo.so = 2 + pid_of_nice # output: # 88048000-88049000 r-xp 00000000 03:07 2207 foo.so # load_bias is 0x80000000 # 88049000-8804a000 rw-p 00000000 03:07 2207 foo.so gdb foo.so <pid_of_foo.so> # Attach to process, and look at its memory. x/64x $esp # and continue until seeing the AT_* on the stack. I see # 0xbffffa90: 0xbfffffe8 0x00000000 0x00000003 0x90090034 # 0xbffffaa0: 0x00000004 0x00000020 0x00000005 0x00000005 # 0xbffffab0: 0x00000006 0x00001000 0x00000007 0x40000000 # 0xbffffac0: 0x00000008 0x00000000 0x00000009 0x88048114 # which shows AT_PHDR at 0xbffffa9c of 0x90090034 # which is too big by 0x08048000 [p_vaddr of first PT_LOAD] # because the correct value is 0x88048034. # Note that AT_ENTRY at 0xbffffacc is 0x88048114 which is correct. -- John Reiser, [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/