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invert_pt_dynamic() DT_GNU_HASH trims hash array for Rust and Android

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https://github.com/upx/upx/issues/369
	modified:   p_lx_elf.cpp
This commit is contained in:
John Reiser 2020-04-15 17:29:03 -07:00 committed by Markus F.X.J. Oberhumer
parent 4cb4bd38eb
commit 210870f840
1 changed files with 58 additions and 24 deletions
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82
src/p_lx_elf.cpp
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@ -1675,30 +1675,47 @@ PackLinuxElf32::invert_pt_dynamic(Elf32_Dyn const *dynp)
throwCantPack(msg); throwCantPack(msg);
} }
unsigned const n_bucket = get_te32(&gashtab[0]); unsigned const n_bucket = get_te32(&gashtab[0]);
unsigned const symbias = get_te32(&gashtab[1]);
unsigned const n_bitmask = get_te32(&gashtab[2]); unsigned const n_bitmask = get_te32(&gashtab[2]);
unsigned const gnu_shift = get_te32(&gashtab[3]); unsigned const gnu_shift = get_te32(&gashtab[3]);
unsigned const *const bitmask = (unsigned const *)(void const *)&gashtab[4]; unsigned const *const bitmask = (unsigned const *)(void const *)&gashtab[4];
unsigned const *const buckets = (unsigned const *)&bitmask[n_bitmask]; unsigned const *const buckets = (unsigned const *)&bitmask[n_bitmask];
unsigned const *const hasharr = &buckets[n_bucket]; (void)hasharr; unsigned const *const hasharr = &buckets[n_bucket]; (void)hasharr;
//unsigned const *const gashend = &hasharr[n_bucket]; // minimum //unsigned const *const gashend = &hasharr[n_bucket]; // minimum, except:
// Rust and Android trim unused zeroes from high end of hasharr[]
unsigned bmax = 0;
for (unsigned j= 0; j < n_bucket; ++j) {
if (buckets[j]) {
if (bmax < buckets[j]) {
bmax = buckets[j];
}
}
}
if (bmax < symbias) {
char msg[80]; snprintf(msg, sizeof(msg),
"bad DT_GNU_HASH max_bucket=%#x < symbias=%#x", bmax, symbias);
throwCantPack(msg);
}
bmax -= symbias;
unsigned const v_sym = !x_sym ? 0 : get_te32(&dynp0[-1+ x_sym].d_val); unsigned const v_sym = !x_sym ? 0 : get_te32(&dynp0[-1+ x_sym].d_val);
unsigned r = 0;
if (!n_bucket || !n_bitmask || !v_sym if (!n_bucket || !n_bitmask || !v_sym
|| (-1+ n_bitmask) & n_bitmask // not a power of 2 || (r=1, ((-1+ n_bitmask) & n_bitmask)) // not a power of 2
|| 8*sizeof(unsigned) <= gnu_shift // shifted result always == 0 || (r=2, (8*sizeof(unsigned) <= gnu_shift)) // shifted result always == 0
|| (n_bucket>>30) // fie on fuzzers || (r=3, (n_bucket>>30)) // fie on fuzzers
|| (n_bitmask>>30) || (r=4, (n_bitmask>>30))
|| (file_size / sizeof(unsigned)) <= (n_bitmask + 2*n_bucket) // FIXME: weak || (r=5, ((file_size/sizeof(unsigned))
// FIXME: next test does work for Android? <= ((sizeof(*bitmask)/sizeof(unsigned))*n_bitmask + 2*n_bucket))) // FIXME: weak
|| ((v_gsh < v_sym) && (v_sym - v_gsh) < (sizeof(unsigned)*4 // headers || (r=6, ((v_gsh < v_sym) && (v_sym - v_gsh) < (sizeof(unsigned)*4 // headers
+ sizeof(*bitmask)*n_bitmask // bitmask + sizeof(*bitmask)*n_bitmask // bitmask
+ sizeof(*buckets)*n_bucket // buckets + sizeof(*buckets)*n_bucket // buckets
+ sizeof(*hasharr)*n_bucket // hasharr + sizeof(*hasharr)*(1+ bmax) // hasharr
)) )) )
) { ) {
char msg[90]; snprintf(msg, sizeof(msg), char msg[90]; snprintf(msg, sizeof(msg),
"bad DT_GNU_HASH n_bucket=%#x n_bitmask=%#x len=%#x", "bad DT_GNU_HASH n_bucket=%#x n_bitmask=%#x len=%#lx r=%d",
n_bucket, n_bitmask, v_sym - v_gsh); n_bucket, n_bitmask, (long unsigned)(v_sym - v_gsh), r);
throwCantPack(msg); throwCantPack(msg);
} }
} }
@ -5189,30 +5206,47 @@ PackLinuxElf64::invert_pt_dynamic(Elf64_Dyn const *dynp)
throwCantPack(msg); throwCantPack(msg);
} }
unsigned const n_bucket = get_te32(&gashtab[0]); unsigned const n_bucket = get_te32(&gashtab[0]);
unsigned const symbias = get_te32(&gashtab[1]);
unsigned const n_bitmask = get_te32(&gashtab[2]); unsigned const n_bitmask = get_te32(&gashtab[2]);
unsigned const gnu_shift = get_te32(&gashtab[3]); unsigned const gnu_shift = get_te32(&gashtab[3]);
upx_uint64_t const *const bitmask = (upx_uint64_t const *)(void const *)&gashtab[4]; upx_uint64_t const *const bitmask = (upx_uint64_t const *)(void const *)&gashtab[4];
unsigned const *const buckets = (unsigned const *)&bitmask[n_bitmask]; unsigned const *const buckets = (unsigned const *)&bitmask[n_bitmask];
unsigned const *const hasharr = &buckets[n_bucket]; (void)hasharr; unsigned const *const hasharr = &buckets[n_bucket]; (void)hasharr;
//unsigned const *const gashend = &hasharr[n_bucket]; // minimum //unsigned const *const gashend = &hasharr[n_bucket]; // minimum, except:
// Rust and Android trim unused zeroes from high end of hasharr[]
unsigned bmax = 0;
for (unsigned j= 0; j < n_bucket; ++j) {
if (buckets[j]) {
if (bmax < buckets[j]) {
bmax = buckets[j];
}
}
}
if (bmax < symbias) {
char msg[80]; snprintf(msg, sizeof(msg),
"bad DT_GNU_HASH max_bucket=%#x < symbias=%#x", bmax, symbias);
throwCantPack(msg);
}
bmax -= symbias;
upx_uint64_t const v_sym = !x_sym ? 0 : get_te64(&dynp0[-1+ x_sym].d_val); upx_uint64_t const v_sym = !x_sym ? 0 : get_te64(&dynp0[-1+ x_sym].d_val);
unsigned r = 0;
if (!n_bucket || !n_bitmask || !v_sym if (!n_bucket || !n_bitmask || !v_sym
|| (-1+ n_bitmask) & n_bitmask // not a power of 2 || (r=1, ((-1+ n_bitmask) & n_bitmask)) // not a power of 2
|| 8*sizeof(upx_uint64_t) <= gnu_shift // shifted result always == 0 || (r=2, (8*sizeof(upx_uint64_t) <= gnu_shift)) // shifted result always == 0
|| (n_bucket>>30) // fie on fuzzers || (r=3, (n_bucket>>30)) // fie on fuzzers
|| (n_bitmask>>30) || (r=4, (n_bitmask>>30))
|| (file_size/sizeof(unsigned)) <= ((sizeof(*bitmask)/sizeof(unsigned))*n_bitmask + 2*n_bucket) // FIXME: weak || (r=5, ((file_size/sizeof(unsigned))
// FIXME: next test does work for Android? <= ((sizeof(*bitmask)/sizeof(unsigned))*n_bitmask + 2*n_bucket))) // FIXME: weak
|| ((v_gsh < v_sym) && (v_sym - v_gsh) < (sizeof(unsigned)*4 // headers || (r=6, ((v_gsh < v_sym) && (v_sym - v_gsh) < (sizeof(unsigned)*4 // headers
+ sizeof(*bitmask)*n_bitmask // bitmask + sizeof(*bitmask)*n_bitmask // bitmask
+ sizeof(*buckets)*n_bucket // buckets + sizeof(*buckets)*n_bucket // buckets
+ sizeof(*hasharr)*n_bucket // hasharr + sizeof(*hasharr)*(1+ bmax) // hasharr
)) )) )
) { ) {
char msg[90]; snprintf(msg, sizeof(msg), char msg[90]; snprintf(msg, sizeof(msg),
"bad DT_GNU_HASH n_bucket=%#x n_bitmask=%#x len=%#lx", "bad DT_GNU_HASH n_bucket=%#x n_bitmask=%#x len=%#lx r=%d",
n_bucket, n_bitmask, (long unsigned)(v_sym - v_gsh)); n_bucket, n_bitmask, (long unsigned)(v_sym - v_gsh), r);
throwCantPack(msg); throwCantPack(msg);
} }
} }