Unverified Commit d1f48210 authored by Zijun Hu's avatar Zijun Hu Committed by Christian Brauner
Browse files

fs/fs_parse: Remove unused and problematic validate_constant_table() 



Remove validate_constant_table() since:

- It has no caller.

- It has below 3 bugs for good constant table array array[] which must
  end with a empty entry, and take below invocation for explaination:
  validate_constant_table(array, ARRAY_SIZE(array), ...)

  - Always return wrong value due to the last empty entry.
  - Imprecise error message for missorted case.
  - Potential NULL pointer dereference since the last pr_err() may use
    @tbl[i].name NULL pointer to print the last empty entry's name.

Signed-off-by: default avatarZijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/20250415-fix_fs-v4-1-5d575124a3ff@quicinc.com


Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 296b6705

Documentation/filesystems/mount_api.rst

+0 −15
Original line number Diff line number Diff line
@@ -752,21 +752,6 @@ process the parameters it is given. 
     If a match is found, the corresponding value is returned.  If a match

     isn't found, the not_found value is returned instead.



   * ::



       bool validate_constant_table(const struct constant_table *tbl,

				    size_t tbl_size,

				    int low, int high, int special);



     Validate a constant table.  Checks that all the elements are appropriately

     ordered, that there are no duplicates and that the values are between low

     and high inclusive, though provision is made for one allowable special

     value outside of that range.  If no special value is required, special

     should just be set to lie inside the low-to-high range.



     If all is good, true is returned.  If the table is invalid, errors are

     logged to the kernel log buffer and false is returned.



   * ::



       bool fs_validate_description(const char *name,

fs/fs_parser.c

+0 −49
Original line number Diff line number Diff line
@@ -379,55 +379,6 @@ int fs_param_is_path(struct p_log *log, const struct fs_parameter_spec *p, 
EXPORT_SYMBOL(fs_param_is_path);



#ifdef CONFIG_VALIDATE_FS_PARSER

/**

 * validate_constant_table - Validate a constant table

 * @tbl: The constant table to validate.

 * @tbl_size: The size of the table.

 * @low: The lowest permissible value.

 * @high: The highest permissible value.

 * @special: One special permissible value outside of the range.

 */

bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,

			     int low, int high, int special)

{

	size_t i;

	bool good = true;



	if (tbl_size == 0) {

		pr_warn("VALIDATE C-TBL: Empty\n");

		return true;

	}



	for (i = 0; i < tbl_size; i++) {

		if (!tbl[i].name) {

			pr_err("VALIDATE C-TBL[%zu]: Null\n", i);

			good = false;

		} else if (i > 0 && tbl[i - 1].name) {

			int c = strcmp(tbl[i-1].name, tbl[i].name);



			if (c == 0) {

				pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n",

				       i, tbl[i].name);

				good = false;

			}

			if (c > 0) {

				pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n",

				       i, tbl[i-1].name, tbl[i].name);

				good = false;

			}

		}



		if (tbl[i].value != special &&

		    (tbl[i].value < low || tbl[i].value > high)) {

			pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n",

			       i, tbl[i].name, tbl[i].value, low, high);

			good = false;

		}

	}



	return good;

}



/**

 * fs_validate_description - Validate a parameter specification array

 * @name: Owner name of the parameter specification array

include/linux/fs_parser.h

+0 −5
Original line number Diff line number Diff line
@@ -87,14 +87,9 @@ extern int lookup_constant(const struct constant_table tbl[], const char *name, 
extern const struct constant_table bool_names[];



#ifdef CONFIG_VALIDATE_FS_PARSER

extern bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,

				    int low, int high, int special);

extern bool fs_validate_description(const char *name,

				    const struct fs_parameter_spec *desc);

#else

static inline bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,

					   int low, int high, int special)

{ return true; }

static inline bool fs_validate_description(const char *name,

					   const struct fs_parameter_spec *desc)

{ return true; }