69 lines
2.3 KiB
Diff
69 lines
2.3 KiB
Diff
commit cf8c6a634c0a04a9f5d198ef05310f85f7338839
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Author: Florian Weimer <fweimer@redhat.com>
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Date: Fri Nov 5 17:01:24 2021 +0100
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elf: Earlier missing dynamic segment check in _dl_map_object_from_fd
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Separated debuginfo files have PT_DYNAMIC with p_filesz == 0. We
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need to check for that before the _dl_map_segments call because
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that could attempt to write to mappings that extend beyond the end
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of the file, resulting in SIGBUS.
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Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
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(cherry picked from commit ea32ec354c65ddad11b82ca9d057010df13a9cea)
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diff --git a/elf/dl-load.c b/elf/dl-load.c
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index 4445c28ef3fb4a7e..0976977fbdf21902 100644
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--- a/elf/dl-load.c
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+++ b/elf/dl-load.c
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@@ -1130,6 +1130,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
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struct loadcmd loadcmds[l->l_phnum];
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size_t nloadcmds = 0;
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bool has_holes = false;
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+ bool empty_dynamic = false;
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/* The struct is initialized to zero so this is not necessary:
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l->l_ld = 0;
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@@ -1142,7 +1143,9 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
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segments are mapped in. We record the addresses it says
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verbatim, and later correct for the run-time load address. */
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case PT_DYNAMIC:
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- if (ph->p_filesz)
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+ if (ph->p_filesz == 0)
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+ empty_dynamic = true; /* Usually separate debuginfo. */
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+ else
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{
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/* Debuginfo only files from "objcopy --only-keep-debug"
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contain a PT_DYNAMIC segment with p_filesz == 0. Skip
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@@ -1265,6 +1268,13 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
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goto lose;
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}
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+ /* This check recognizes most separate debuginfo files. */
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+ if (__glibc_unlikely ((l->l_ld == 0 && type == ET_DYN) || empty_dynamic))
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+ {
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+ errstring = N_("object file has no dynamic section");
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+ goto lose;
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+ }
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+
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/* Length of the sections to be loaded. */
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maplength = loadcmds[nloadcmds - 1].allocend - loadcmds[0].mapstart;
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@@ -1282,15 +1292,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
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}
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}
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- if (l->l_ld == 0)
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- {
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- if (__glibc_unlikely (type == ET_DYN))
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- {
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- errstring = N_("object file has no dynamic section");
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- goto lose;
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- }
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- }
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- else
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+ if (l->l_ld != 0)
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l->l_ld = (ElfW(Dyn) *) ((ElfW(Addr)) l->l_ld + l->l_addr);
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elf_get_dynamic_info (l);
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