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Hi! l_text_end is not set at this point yet and even if it would, if first PT_LOAD segment is not executable, it would still be 0. Doing mprotect (0, up to few MB, PROT_NONE) is bad and mprotecting l->l_laddr + c->mapend is really what is needed. Before this patch ld.so did: strace /lib64/ld-linux-x86-64.so.2 /bin/echo ... open("/lib64/tls/libc.so.6", O_RDONLY) = 4 ... mmap(0x3072d00000, 2137672, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x3072d00000 mprotect(0, 970312, PROT_NONE) = -1 ENOMEM (Cannot allocate memory) mmap(0x3072f00000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x200000) = 0x3072f00000 ... mprotect(0x3072f00000, 16384, PROT_READ) = 0 ... for libc.so.6: readelf -Wl /lib64/tls/libc.so.6 | egrep LOAD\|RELRO LOAD 0x000000 0x0000003072d00000 0x0000003072d00000 0x11c72b 0x11c72b R E 0x100000 LOAD 0x200f30 0x0000003072f00f30 0x0000003072f00f30 0x004ad0 0x008f18 RW 0x100000 GNU_RELRO 0x200f30 0x0000003072f00f30 0x0000003072f00f30 0x0030d0 0x0030d0 R 0x1 With this patch: strace elf/ld.so /bin/echo ... open("/lib64/tls/libc.so.6", O_RDONLY) = 4 ... mmap(0x3072d00000, 2137672, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x3072d00000 mprotect(0x3072e1d000, 970312, PROT_NONE) = 0 mmap(0x3072f00000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x200000) = 0x3072f00000 ... mprotect(0x3072f00000, 16384, PROT_READ) = 0 ... 2004-07-06 Jakub Jelinek <jakub@redhat.com> * elf/dl-load.c (_dl_map_object_from_fd): If has_holes, mprotect l->l_addr + c->mapend instead of l->l_text_end. --- libc/elf/dl-load.c.jj 2004-05-26 16:04:38.000000000 +0200 +++ libc/elf/dl-load.c 2004-07-06 22:21:04.054995231 +0200 @@ -1117,7 +1117,7 @@ cannot allocate TLS data structures for unallocated. Then jump into the normal segment-mapping loop to handle the portion of the segment past the end of the file mapping. */ - __mprotect ((caddr_t) l->l_text_end, + __mprotect ((caddr_t) (l->l_addr + c->mapend), loadcmds[nloadcmds - 1].allocend - c->mapend, PROT_NONE); Jakub
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