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authorPeter Maydell <peter.maydell@linaro.org>2017-11-07 18:25:18 +0000
committerRiku Voipio <riku.voipio@linaro.org>2017-11-20 16:15:41 +0200
commitf516511ea84d8bb3395d6ea95a7c7b80dc2a05e9 (patch)
treeeede4ad1c8d5100f1ad9cb19a31fc971fba62e74
parent78bfef72fbf8705f002c5c57cf3f1d3b8e83399e (diff)
downloadqemu-linux-user-for-upstream.tar.gz
linux-user: Fix calculation of auxv lengthpull-linux-user-20171120linux-user-for-upstream
In commit 7c4ee5bcc82e643 we changed the order in which we construct the AUXV, but forgot to adjust the calculation of the length. The result is that we set info->auxv_len to a bogus and negative value, and then later on the code in open_self_auxv() gets confused and ends up presenting the guest with an empty file. Since we now have to calculate the auxv length up-front as part of figuring out how much we're going to put on the stack, set info->auxv_len then; this allows us to assert that we put the same number of entries into auxv as we pre-calculated, rather than merely having a comment saying we need to do that. Fixes: https://bugs.launchpad.net/qemu/+bug/1728116 Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
-rw-r--r--linux-user/elfload.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 3b857fbc9c..20f3d8c2c3 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1732,6 +1732,8 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
#ifdef ELF_HWCAP2
size += 2;
#endif
+ info->auxv_len = size * n;
+
size += envc + argc + 2;
size += 1; /* argc itself */
size *= n;
@@ -1760,7 +1762,6 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
put_user_ual(val, u_auxv); u_auxv += n; \
} while(0)
- /* There must be exactly DLINFO_ITEMS entries here. */
#ifdef ARCH_DLINFO
/*
* ARCH_DLINFO must come first so platform specific code can enforce
@@ -1768,6 +1769,9 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
*/
ARCH_DLINFO;
#endif
+ /* There must be exactly DLINFO_ITEMS entries here, or the assert
+ * on info->auxv_len will trigger.
+ */
NEW_AUX_ENT(AT_PHDR, (abi_ulong)(info->load_addr + exec->e_phoff));
NEW_AUX_ENT(AT_PHENT, (abi_ulong)(sizeof (struct elf_phdr)));
NEW_AUX_ENT(AT_PHNUM, (abi_ulong)(exec->e_phnum));
@@ -1793,7 +1797,10 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
NEW_AUX_ENT (AT_NULL, 0);
#undef NEW_AUX_ENT
- info->auxv_len = u_argv - info->saved_auxv;
+ /* Check that our initial calculation of the auxv length matches how much
+ * we actually put into it.
+ */
+ assert(info->auxv_len == u_auxv - info->saved_auxv);
put_user_ual(argc, u_argc);