LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Vadym Kochan <vadym.kochan@plvision.eu>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org
Cc: Vadym Kochan <vadym.kochan@plvision.eu>
Subject: [PATCH v3] nvmem: core: fix possibly memleak when use nvmem_cell_info_to_nvmem_cell()
Date: Wed, 23 Sep 2020 23:44:56 +0300
Message-ID: <20200923204456.14032-1-vadym.kochan@plvision.eu> (raw)

Fix missing 'kfree_const(cell->name)' when call to
nvmem_cell_info_to_nvmem_cell() in several places:

     * after nvmem_cell_info_to_nvmem_cell() failed during
       nvmem_add_cells()

     * during nvmem_device_cell_{read,write} when cell->name is
       kstrdup'ed() without calling kfree_const() at the end, but
       really there is no reason to do that 'dup, because the cell
       instance is allocated on the stack for some short period to be
       read/write without exposing it to the caller.

So the new nvmem_cell_info_to_nvmem_cell_nodup() helper is introduced
which is used to convert cell_info -> cell without name duplication as
a lighweight version of nvmem_cell_info_to_nvmem_cell().

Fixes: e2a5402ec7c6 ("nvmem: Add nvmem_device based consumer apis.")
Signed-off-by: Vadym Kochan <vadym.kochan@plvision.eu>
---
v3:
    * rename __nvmem_cell_info_to_nvmem_cell() -> nvmem_cell_info_to_nvmem_cell_nodup()

    * rephrase commit description a bit

    * get rid of wrong func line wrapping

v2:
    * remove not needed 'kfree_const(cell->name)' after nvmem_cell_info_to_nvmem_cell()
      failed.

 drivers/nvmem/core.c | 33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 6cd3edb2eaf6..10cd935cf30e 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -361,16 +361,14 @@ static void nvmem_cell_add(struct nvmem_cell *cell)
 	blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
 }
 
-static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
-				   const struct nvmem_cell_info *info,
-				   struct nvmem_cell *cell)
+static int nvmem_cell_info_to_nvmem_cell_nodup(struct nvmem_device *nvmem,
+					const struct nvmem_cell_info *info,
+					struct nvmem_cell *cell)
 {
 	cell->nvmem = nvmem;
 	cell->offset = info->offset;
 	cell->bytes = info->bytes;
-	cell->name = kstrdup_const(info->name, GFP_KERNEL);
-	if (!cell->name)
-		return -ENOMEM;
+	cell->name = info->name;
 
 	cell->bit_offset = info->bit_offset;
 	cell->nbits = info->nbits;
@@ -382,13 +380,30 @@ static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
 	if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
 		dev_err(&nvmem->dev,
 			"cell %s unaligned to nvmem stride %d\n",
-			cell->name, nvmem->stride);
+			cell->name ?: "<unknown>", nvmem->stride);
 		return -EINVAL;
 	}
 
 	return 0;
 }
 
+static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem,
+				const struct nvmem_cell_info *info,
+				struct nvmem_cell *cell)
+{
+	int err;
+
+	err = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, cell);
+	if (err)
+		return err;
+
+	cell->name = kstrdup_const(info->name, GFP_KERNEL);
+	if (!cell->name)
+		return -ENOMEM;
+
+	return 0;
+}
+
 /**
  * nvmem_add_cells() - Add cell information to an nvmem device
  *
@@ -1460,7 +1475,7 @@ ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
 	if (!nvmem)
 		return -EINVAL;
 
-	rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
+	rc = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, &cell);
 	if (rc)
 		return rc;
 
@@ -1490,7 +1505,7 @@ int nvmem_device_cell_write(struct nvmem_device *nvmem,
 	if (!nvmem)
 		return -EINVAL;
 
-	rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell);
+	rc = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, &cell);
 	if (rc)
 		return rc;
 
-- 
2.17.1


             reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-23 20:44 Vadym Kochan [this message]
2020-09-25  9:32 ` Srinivas Kandagatla
2020-09-27 12:25   ` Greg Kroah-Hartman

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200923204456.14032-1-vadym.kochan@plvision.eu \
    --to=vadym.kochan@plvision.eu \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=srinivas.kandagatla@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git