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tests: Correction to vg_prepare_blob()

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vg_prepare_blob() assumes a valid return from fdt_num_mem_rsv() in order
to make sensible initialization of the valgrind mem checker.  Usually
that's fine, but it breaks down on the (deliberately corrupted)
truncated_memrsv testcase.

That led to marking a negative-size (== enormously sized once cast to
size_t) as defined with VALGRIND_MAKE_MEM_DEFINED, which casued valgrind
to freeze up and consume ludicrous amounts of memory until OOMing.

This correction makes us robust in that case.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
David Gibson 2018-07-23 12:16:09 +10:00
parent 57f7f9e7bc
commit 85bce8b2f0
1 changed files with 8 additions and 6 deletions
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14
tests/testutils.c
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@ -168,18 +168,22 @@ void vg_prepare_blob(void *fdt, size_t bufsize)
{ {
char *blob = fdt; char *blob = fdt;
int off_memrsv, off_strings, off_struct; int off_memrsv, off_strings, off_struct;
int num_memrsv;
size_t size_memrsv, size_strings, size_struct; size_t size_memrsv, size_strings, size_struct;
size_memrsv = (fdt_num_mem_rsv(fdt) + 1) off_memrsv = fdt_off_mem_rsvmap(fdt);
* sizeof(struct fdt_reserve_entry); num_memrsv = fdt_num_mem_rsv(fdt);
if (num_memrsv < 0)
size_memrsv = fdt_totalsize(fdt) - off_memrsv;
else
size_memrsv = (num_memrsv + 1)
* sizeof(struct fdt_reserve_entry);
VALGRIND_MAKE_MEM_UNDEFINED(blob, bufsize); VALGRIND_MAKE_MEM_UNDEFINED(blob, bufsize);
VALGRIND_MAKE_MEM_DEFINED(blob, FDT_V1_SIZE); VALGRIND_MAKE_MEM_DEFINED(blob, FDT_V1_SIZE);
VALGRIND_MAKE_MEM_DEFINED(blob, fdt_header_size(fdt)); VALGRIND_MAKE_MEM_DEFINED(blob, fdt_header_size(fdt));
if (fdt_magic(fdt) == FDT_MAGIC) { if (fdt_magic(fdt) == FDT_MAGIC) {
off_memrsv = fdt_off_mem_rsvmap(fdt);
off_strings = fdt_off_dt_strings(fdt); off_strings = fdt_off_dt_strings(fdt);
if (fdt_version(fdt) >= 3) if (fdt_version(fdt) >= 3)
size_strings = fdt_size_dt_strings(fdt); size_strings = fdt_size_dt_strings(fdt);
@ -192,8 +196,6 @@ void vg_prepare_blob(void *fdt, size_t bufsize)
else else
size_struct = fdt_totalsize(fdt) - off_struct; size_struct = fdt_totalsize(fdt) - off_struct;
} else if (fdt_magic(fdt) == FDT_SW_MAGIC) { } else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
off_memrsv = fdt_off_mem_rsvmap(fdt);
size_strings = fdt_size_dt_strings(fdt); size_strings = fdt_size_dt_strings(fdt);
off_strings = fdt_off_dt_strings(fdt) - size_strings; off_strings = fdt_off_dt_strings(fdt) - size_strings;