From: Demi Marie Obenour <demi@invisiblethingslab.com> To: Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@kernel.org>, dm-devel@redhat.com Cc: Demi Marie Obenour <demi@invisiblethingslab.com>, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 3/6] device-mapper: structs and parameter strings must not overlap Date: Thu, 1 Jun 2023 17:24:52 -0400 [thread overview] Message-ID: <20230601212456.1533-4-demi@invisiblethingslab.com> (raw) In-Reply-To: <20230601212456.1533-1-demi@invisiblethingslab.com> The NUL terminator for each target parameter string must precede the following 'struct dm_target_spec'. Otherwise, dm_split_args() might corrupt this struct. Furthermore, the first 'struct dm_target_spec' must come after the 'struct dm_ioctl', as if it overlaps too much dm_split_args() could corrupt the 'struct dm_ioctl'. Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org --- drivers/md/dm-ioctl.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 64e8f16d344c47057de5e2d29e3d63202197dca0..da6ca26b51d0953df380582bb3a51c2ec22c27cb 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1391,7 +1391,7 @@ static inline fmode_t get_mode(struct dm_ioctl *param) return mode; } -static int next_target(struct dm_target_spec *last, uint32_t next, void *end, +static int next_target(struct dm_target_spec *last, uint32_t next, const char *end, struct dm_target_spec **spec, char **target_params) { static_assert(_Alignof(struct dm_target_spec) <= 8, @@ -1404,7 +1404,7 @@ static int next_target(struct dm_target_spec *last, uint32_t next, void *end, * sizeof(struct dm_target_spec) or more, as otherwise *last was * out of bounds already. */ - size_t remaining = (char *)end - (char *)last; + size_t remaining = end - (char *)last; /* * There must be room for both the next target spec and the @@ -1423,10 +1423,7 @@ static int next_target(struct dm_target_spec *last, uint32_t next, void *end, *spec = (struct dm_target_spec *) ((unsigned char *) last + next); *target_params = (char *) (*spec + 1); - if (*spec < (last + 1)) - return -EINVAL; - - return invalid_str(*target_params, end); + return 0; } static int populate_table(struct dm_table *table, @@ -1436,8 +1433,9 @@ static int populate_table(struct dm_table *table, unsigned int i = 0; struct dm_target_spec *spec = (struct dm_target_spec *) param; uint32_t next = param->data_start; - void *end = (void *) param + param_size; + const char *const end = (const char *) param + param_size; char *target_params; + size_t min_size = sizeof(struct dm_ioctl); if (!param->target_count) { DMERR("%s: no targets specified", __func__); @@ -1445,6 +1443,13 @@ static int populate_table(struct dm_table *table, } for (i = 0; i < param->target_count; i++) { + const char *nul_terminator; + + if (next < min_size) { + DMERR("%s: next target spec (offset %u) overlaps %s", + __func__, next, i ? "previous target" : "'struct dm_ioctl'"); + return -EINVAL; + } r = next_target(spec, next, end, &spec, &target_params); if (r) { @@ -1452,6 +1457,15 @@ static int populate_table(struct dm_table *table, return r; } + nul_terminator = memchr(target_params, 0, (size_t)(end - target_params)); + if (nul_terminator == NULL) { + DMERR("%s: target parameters not NUL-terminated", __func__); + return -EINVAL; + } + + /* Add 1 for NUL terminator */ + min_size = (size_t)(nul_terminator - (const char *)spec) + 1; + r = dm_table_add_target(table, spec->target_type, (sector_t) spec->sector_start, (sector_t) spec->length, -- Sincerely, Demi Marie Obenour (she/her/hers) Invisible Things Lab
WARNING: multiple messages have this Message-ID (diff)
From: Demi Marie Obenour <demi@invisiblethingslab.com> To: Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@kernel.org>, dm-devel@redhat.com Cc: Demi Marie Obenour <demi@invisiblethingslab.com>, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [dm-devel] [PATCH 3/6] device-mapper: structs and parameter strings must not overlap Date: Thu, 1 Jun 2023 17:24:52 -0400 [thread overview] Message-ID: <20230601212456.1533-4-demi@invisiblethingslab.com> (raw) In-Reply-To: <20230601212456.1533-1-demi@invisiblethingslab.com> The NUL terminator for each target parameter string must precede the following 'struct dm_target_spec'. Otherwise, dm_split_args() might corrupt this struct. Furthermore, the first 'struct dm_target_spec' must come after the 'struct dm_ioctl', as if it overlaps too much dm_split_args() could corrupt the 'struct dm_ioctl'. Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org --- drivers/md/dm-ioctl.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 64e8f16d344c47057de5e2d29e3d63202197dca0..da6ca26b51d0953df380582bb3a51c2ec22c27cb 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1391,7 +1391,7 @@ static inline fmode_t get_mode(struct dm_ioctl *param) return mode; } -static int next_target(struct dm_target_spec *last, uint32_t next, void *end, +static int next_target(struct dm_target_spec *last, uint32_t next, const char *end, struct dm_target_spec **spec, char **target_params) { static_assert(_Alignof(struct dm_target_spec) <= 8, @@ -1404,7 +1404,7 @@ static int next_target(struct dm_target_spec *last, uint32_t next, void *end, * sizeof(struct dm_target_spec) or more, as otherwise *last was * out of bounds already. */ - size_t remaining = (char *)end - (char *)last; + size_t remaining = end - (char *)last; /* * There must be room for both the next target spec and the @@ -1423,10 +1423,7 @@ static int next_target(struct dm_target_spec *last, uint32_t next, void *end, *spec = (struct dm_target_spec *) ((unsigned char *) last + next); *target_params = (char *) (*spec + 1); - if (*spec < (last + 1)) - return -EINVAL; - - return invalid_str(*target_params, end); + return 0; } static int populate_table(struct dm_table *table, @@ -1436,8 +1433,9 @@ static int populate_table(struct dm_table *table, unsigned int i = 0; struct dm_target_spec *spec = (struct dm_target_spec *) param; uint32_t next = param->data_start; - void *end = (void *) param + param_size; + const char *const end = (const char *) param + param_size; char *target_params; + size_t min_size = sizeof(struct dm_ioctl); if (!param->target_count) { DMERR("%s: no targets specified", __func__); @@ -1445,6 +1443,13 @@ static int populate_table(struct dm_table *table, } for (i = 0; i < param->target_count; i++) { + const char *nul_terminator; + + if (next < min_size) { + DMERR("%s: next target spec (offset %u) overlaps %s", + __func__, next, i ? "previous target" : "'struct dm_ioctl'"); + return -EINVAL; + } r = next_target(spec, next, end, &spec, &target_params); if (r) { @@ -1452,6 +1457,15 @@ static int populate_table(struct dm_table *table, return r; } + nul_terminator = memchr(target_params, 0, (size_t)(end - target_params)); + if (nul_terminator == NULL) { + DMERR("%s: target parameters not NUL-terminated", __func__); + return -EINVAL; + } + + /* Add 1 for NUL terminator */ + min_size = (size_t)(nul_terminator - (const char *)spec) + 1; + r = dm_table_add_target(table, spec->target_type, (sector_t) spec->sector_start, (sector_t) spec->length, -- Sincerely, Demi Marie Obenour (she/her/hers) Invisible Things Lab -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel
next prev parent reply other threads:[~2023-06-01 21:25 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-06-01 21:24 [PATCH 0/6] Several device-mapper fixes Demi Marie Obenour 2023-06-01 21:24 ` [dm-devel] " Demi Marie Obenour 2023-06-01 21:24 ` [PATCH 1/6] device-mapper: Check that target specs are sufficiently aligned Demi Marie Obenour 2023-06-01 21:24 ` [dm-devel] " Demi Marie Obenour 2023-06-01 21:24 ` [PATCH 2/6] device-mapper: Avoid pointer arithmetic overflow Demi Marie Obenour 2023-06-01 21:24 ` [dm-devel] " Demi Marie Obenour 2023-06-01 21:24 ` Demi Marie Obenour [this message] 2023-06-01 21:24 ` [dm-devel] [PATCH 3/6] device-mapper: structs and parameter strings must not overlap Demi Marie Obenour 2023-06-01 21:24 ` [PATCH 4/6] device-mapper: Avoid double-fetch of version Demi Marie Obenour 2023-06-01 21:24 ` [dm-devel] " Demi Marie Obenour 2023-06-03 7:40 ` kernel test robot 2023-06-03 7:40 ` [dm-devel] " kernel test robot 2023-06-03 14:21 ` Demi Marie Obenour 2023-06-03 14:21 ` [dm-devel] " Demi Marie Obenour 2023-06-01 21:24 ` [PATCH 5/6] device-mapper: Refuse to create device named "control" Demi Marie Obenour 2023-06-01 21:24 ` [dm-devel] " Demi Marie Obenour 2023-06-01 21:24 ` [PATCH 6/6] device-mapper: "." and ".." are not valid symlink names Demi Marie Obenour 2023-06-01 21:24 ` [dm-devel] " Demi Marie Obenour 2023-06-03 14:52 ` [PATCH v2 0/6] Several device-mapper fixes Demi Marie Obenour 2023-06-03 14:52 ` [dm-devel] " Demi Marie Obenour 2023-06-03 14:52 ` [PATCH v2 1/6] device-mapper: Check that target specs are sufficiently aligned Demi Marie Obenour 2023-06-03 14:52 ` [dm-devel] " Demi Marie Obenour 2023-06-22 16:28 ` Mike Snitzer 2023-06-22 16:28 ` [dm-devel] " Mike Snitzer 2023-06-22 19:51 ` Demi Marie Obenour 2023-06-22 19:51 ` [dm-devel] " Demi Marie Obenour 2023-06-22 22:54 ` Mike Snitzer 2023-06-22 22:54 ` Mike Snitzer 2023-06-22 17:29 ` [dm-devel] " Mikulas Patocka 2023-06-22 17:29 ` Mikulas Patocka 2023-06-22 20:27 ` Demi Marie Obenour 2023-06-22 20:27 ` Demi Marie Obenour 2023-06-03 14:52 ` [PATCH v2 2/6] device-mapper: Avoid pointer arithmetic overflow Demi Marie Obenour 2023-06-03 14:52 ` [dm-devel] " Demi Marie Obenour 2023-06-22 17:30 ` Mikulas Patocka 2023-06-22 17:30 ` Mikulas Patocka 2023-06-22 22:50 ` Mike Snitzer 2023-06-22 22:50 ` [dm-devel] " Mike Snitzer 2023-06-03 14:52 ` [PATCH v2 3/6] device-mapper: structs and parameter strings must not overlap Demi Marie Obenour 2023-06-03 14:52 ` [dm-devel] " Demi Marie Obenour 2023-06-22 17:31 ` Mikulas Patocka 2023-06-22 17:31 ` Mikulas Patocka 2023-06-03 14:52 ` [PATCH v2 4/6] device-mapper: Avoid double-fetch of version Demi Marie Obenour 2023-06-03 14:52 ` [dm-devel] " Demi Marie Obenour 2023-06-22 16:20 ` Mike Snitzer 2023-06-22 16:20 ` [dm-devel] " Mike Snitzer 2023-06-22 18:43 ` Demi Marie Obenour 2023-06-22 18:43 ` [dm-devel] " Demi Marie Obenour 2023-06-03 14:52 ` [PATCH v2 5/6] device-mapper: Refuse to create device named "control" Demi Marie Obenour 2023-06-03 14:52 ` [dm-devel] " Demi Marie Obenour 2023-06-03 14:52 ` [PATCH v2 6/6] device-mapper: "." and ".." are not valid symlink names Demi Marie Obenour 2023-06-03 14:52 ` [dm-devel] " Demi Marie Obenour
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