| Message ID | 20210109113305.11035-1-dinghao.liu@zju.edu.cn (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | evm: Fix memleak in init_desc | expand |
On Sat, Jan 09, 2021 at 07:33:05PM +0800, Dinghao Liu wrote: > When kmalloc() fails, tmp_tfm allocated by > crypto_alloc_shash() has not been freed, which > leads to memleak. > > Fixes: d46eb3699502b ("evm: crypto hash replaced by shash") > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > --- > security/integrity/evm/evm_crypto.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c > index 168c3b78ac47..39fb31a638ac 100644 > --- a/security/integrity/evm/evm_crypto.c > +++ b/security/integrity/evm/evm_crypto.c > @@ -73,7 +73,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > { > long rc; > const char *algo; > - struct crypto_shash **tfm, *tmp_tfm; > + struct crypto_shash **tfm, *tmp_tfm = NULL; > struct shash_desc *desc; > > if (type == EVM_XATTR_HMAC) { > @@ -118,13 +118,18 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > alloc: > desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm), > GFP_KERNEL); > - if (!desc) > + if (!desc) { > + if (tmp_tfm) > + crypto_free_shash(tmp_tfm); > return ERR_PTR(-ENOMEM); > + } > > desc->tfm = *tfm; > > rc = crypto_shash_init(desc); > if (rc) { > + if (tmp_tfm) > + crypto_free_shash(tmp_tfm); > kfree(desc); > return ERR_PTR(rc); > } There's no need to check for NULL before calling crypto_free_shash(). - Eric
> On Sat, Jan 09, 2021 at 07:33:05PM +0800, Dinghao Liu wrote: > > When kmalloc() fails, tmp_tfm allocated by > > crypto_alloc_shash() has not been freed, which > > leads to memleak. > > > > Fixes: d46eb3699502b ("evm: crypto hash replaced by shash") > > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > > --- > > security/integrity/evm/evm_crypto.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c > > index 168c3b78ac47..39fb31a638ac 100644 > > --- a/security/integrity/evm/evm_crypto.c > > +++ b/security/integrity/evm/evm_crypto.c > > @@ -73,7 +73,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > > { > > long rc; > > const char *algo; > > - struct crypto_shash **tfm, *tmp_tfm; > > + struct crypto_shash **tfm, *tmp_tfm = NULL; > > struct shash_desc *desc; > > > > if (type == EVM_XATTR_HMAC) { > > @@ -118,13 +118,18 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > > alloc: > > desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm), > > GFP_KERNEL); > > - if (!desc) > > + if (!desc) { > > + if (tmp_tfm) > > + crypto_free_shash(tmp_tfm); > > return ERR_PTR(-ENOMEM); > > + } > > > > desc->tfm = *tfm; > > > > rc = crypto_shash_init(desc); > > if (rc) { > > + if (tmp_tfm) > > + crypto_free_shash(tmp_tfm); > > kfree(desc); > > return ERR_PTR(rc); > > } > > There's no need to check for NULL before calling crypto_free_shash(). > I find there is a crypto_shash_tfm() in the definition of crypto_free_shash(). Will this lead to null pointer dereference when we use it to free a NULL pointer? Regards, Dinghao
On Sun, Jan 10, 2021 at 01:27:09PM +0800, dinghao.liu@zju.edu.cn wrote: > > On Sat, Jan 09, 2021 at 07:33:05PM +0800, Dinghao Liu wrote: > > > When kmalloc() fails, tmp_tfm allocated by > > > crypto_alloc_shash() has not been freed, which > > > leads to memleak. > > > > > > Fixes: d46eb3699502b ("evm: crypto hash replaced by shash") > > > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > > > --- > > > security/integrity/evm/evm_crypto.c | 9 +++++++-- > > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > > > diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c > > > index 168c3b78ac47..39fb31a638ac 100644 > > > --- a/security/integrity/evm/evm_crypto.c > > > +++ b/security/integrity/evm/evm_crypto.c > > > @@ -73,7 +73,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > > > { > > > long rc; > > > const char *algo; > > > - struct crypto_shash **tfm, *tmp_tfm; > > > + struct crypto_shash **tfm, *tmp_tfm = NULL; > > > struct shash_desc *desc; > > > > > > if (type == EVM_XATTR_HMAC) { > > > @@ -118,13 +118,18 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > > > alloc: > > > desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm), > > > GFP_KERNEL); > > > - if (!desc) > > > + if (!desc) { > > > + if (tmp_tfm) > > > + crypto_free_shash(tmp_tfm); > > > return ERR_PTR(-ENOMEM); > > > + } > > > > > > desc->tfm = *tfm; > > > > > > rc = crypto_shash_init(desc); > > > if (rc) { > > > + if (tmp_tfm) > > > + crypto_free_shash(tmp_tfm); > > > kfree(desc); > > > return ERR_PTR(rc); > > > } > > > > There's no need to check for NULL before calling crypto_free_shash(). > > > > I find there is a crypto_shash_tfm() in the definition of > crypto_free_shash(). Will this lead to null pointer dereference > when we use it to free a NULL pointer? > No. It does &tfm->base, not tfm->base. - Eric
> On Sun, Jan 10, 2021 at 01:27:09PM +0800, dinghao.liu@zju.edu.cn wrote: > > > On Sat, Jan 09, 2021 at 07:33:05PM +0800, Dinghao Liu wrote: > > > > When kmalloc() fails, tmp_tfm allocated by > > > > crypto_alloc_shash() has not been freed, which > > > > leads to memleak. > > > > > > > > Fixes: d46eb3699502b ("evm: crypto hash replaced by shash") > > > > Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> > > > > --- > > > > security/integrity/evm/evm_crypto.c | 9 +++++++-- > > > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c > > > > index 168c3b78ac47..39fb31a638ac 100644 > > > > --- a/security/integrity/evm/evm_crypto.c > > > > +++ b/security/integrity/evm/evm_crypto.c > > > > @@ -73,7 +73,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > > > > { > > > > long rc; > > > > const char *algo; > > > > - struct crypto_shash **tfm, *tmp_tfm; > > > > + struct crypto_shash **tfm, *tmp_tfm = NULL; > > > > struct shash_desc *desc; > > > > > > > > if (type == EVM_XATTR_HMAC) { > > > > @@ -118,13 +118,18 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) > > > > alloc: > > > > desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm), > > > > GFP_KERNEL); > > > > - if (!desc) > > > > + if (!desc) { > > > > + if (tmp_tfm) > > > > + crypto_free_shash(tmp_tfm); > > > > return ERR_PTR(-ENOMEM); > > > > + } > > > > > > > > desc->tfm = *tfm; > > > > > > > > rc = crypto_shash_init(desc); > > > > if (rc) { > > > > + if (tmp_tfm) > > > > + crypto_free_shash(tmp_tfm); > > > > kfree(desc); > > > > return ERR_PTR(rc); > > > > } > > > > > > There's no need to check for NULL before calling crypto_free_shash(). > > > > > > > I find there is a crypto_shash_tfm() in the definition of > > crypto_free_shash(). Will this lead to null pointer dereference > > when we use it to free a NULL pointer? > > > > No. It does &tfm->base, not tfm->base. > Thank you for your advice! I will resend a new patch soon. Regards, Dinghao
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index 168c3b78ac47..39fb31a638ac 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -73,7 +73,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) { long rc; const char *algo; - struct crypto_shash **tfm, *tmp_tfm; + struct crypto_shash **tfm, *tmp_tfm = NULL; struct shash_desc *desc; if (type == EVM_XATTR_HMAC) { @@ -118,13 +118,18 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) alloc: desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(*tfm), GFP_KERNEL); - if (!desc) + if (!desc) { + if (tmp_tfm) + crypto_free_shash(tmp_tfm); return ERR_PTR(-ENOMEM); + } desc->tfm = *tfm; rc = crypto_shash_init(desc); if (rc) { + if (tmp_tfm) + crypto_free_shash(tmp_tfm); kfree(desc); return ERR_PTR(rc); }
When kmalloc() fails, tmp_tfm allocated by crypto_alloc_shash() has not been freed, which leads to memleak. Fixes: d46eb3699502b ("evm: crypto hash replaced by shash") Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn> --- security/integrity/evm/evm_crypto.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)