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dm verity: allow optional args to alter primary args handling

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The previous commit ("dm verity: Add optional "try_verify_in_tasklet"
feature") imposed that CRYPTO_ALG_ASYNC mask be used even if the
optional "try_verify_in_tasklet" feature was not specified. This was
because verity_parse_opt_args() was called after handling the primary
args (due to it having data dependencies on having first parsed all
primary args).

Enhance verity_ctr() so that simple optional args, that don't have a
data dependency on primary args parsing, can alter how the primary
args are handled. In practice this means verity_parse_opt_args() gets
called twice. First with the new 'only_modifier_opts' arg set to true,
then again with it set to false _after_ parsing all primary args.

This allows the v->use_tasklet flag to be properly set and then used
when verity_ctr() parses the primary args and then calls
crypto_alloc_ahash() with CRYPTO_ALG_ASYNC conditionally set.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Mike Snitzer 2022-07-26 11:29:50 -04:00
parent 5721d4e5a9
commit df326e7a06
1 changed files with 24 additions and 8 deletions
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32
drivers/md/dm-verity-target.c
View File

@ -1027,7 +1027,8 @@ static int verity_parse_verity_mode(struct dm_verity *v, const char *arg_name)
}
static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
struct dm_verity_sig_opts *verify_args)
struct dm_verity_sig_opts *verify_args,
bool only_modifier_opts)
{
int r;
unsigned argc;
@ -1050,6 +1051,8 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
argc--;
if (verity_is_verity_mode(arg_name)) {
if (only_modifier_opts)
continue;
r = verity_parse_verity_mode(v, arg_name);
if (r) {
ti->error = "Conflicting error handling parameters";
@ -1058,6 +1061,8 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
continue;
} else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
if (only_modifier_opts)
continue;
r = verity_alloc_zero_digest(v);
if (r) {
ti->error = "Cannot allocate zero digest";
@ -1066,6 +1071,8 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
continue;
} else if (!strcasecmp(arg_name, DM_VERITY_OPT_AT_MOST_ONCE)) {
if (only_modifier_opts)
continue;
r = verity_alloc_most_once(v);
if (r)
return r;
@ -1076,12 +1083,16 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
continue;
} else if (verity_is_fec_opt_arg(arg_name)) {
if (only_modifier_opts)
continue;
r = verity_fec_parse_opt_args(as, v, &argc, arg_name);
if (r)
return r;
continue;
} else if (verity_verify_is_sig_opt_arg(arg_name)) {
if (only_modifier_opts)
continue;
r = verity_verify_sig_parse_opt_args(as, v,
verify_args,
&argc, arg_name);
@ -1148,6 +1159,15 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
goto bad;
}
/* Parse optional parameters that modify primary args */
if (argc > 10) {
as.argc = argc - 10;
as.argv = argv + 10;
r = verity_parse_opt_args(&as, v, &verify_args, true);
if (r < 0)
goto bad;
}
if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||
num > 1) {
ti->error = "Invalid version";
@ -1219,11 +1239,8 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
goto bad;
}
/*
* FIXME: CRYPTO_ALG_ASYNC should be conditional on v->use_tasklet
* but verity_parse_opt_args() happens below and has data dep on tfm.
*/
v->tfm = crypto_alloc_ahash(v->alg_name, 0, CRYPTO_ALG_ASYNC);
v->tfm = crypto_alloc_ahash(v->alg_name, 0,
v->use_tasklet ? CRYPTO_ALG_ASYNC : 0);
if (IS_ERR(v->tfm)) {
ti->error = "Cannot initialize hash function";
r = PTR_ERR(v->tfm);
@ -1285,8 +1302,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
if (argc) {
as.argc = argc;
as.argv = argv;
r = verity_parse_opt_args(&as, v, &verify_args);
r = verity_parse_opt_args(&as, v, &verify_args, false);
if (r < 0)
goto bad;
}